Showing posts with label Optical Illusions. Show all posts
Showing posts with label Optical Illusions. Show all posts

Sunday 31 July 2022

Jessie's Prints - Episode 22 - Some Stuff For Friends

This week, I are mostly been printing...  Stuff for Friends

Bigby's Sign of the Horns - Thingiverse 4048680

My current DM Mark is a bit of a metalhead and in honour of his awesome DMing I printed him this equally awesome spell effect for the famous D&D spell Bigby's Hand.  I hope I get to see it in play in the not too distant future. 

Bigby's Sign of the Horns

Baby Yoda Lithophane - Thingiverse 4073323

Printing a Lithophane has been high on my agenda for some time and as I was due to meet my 3 old work pals from the Ministry of Defence what better way to celebrate our reunion after Pandemic.

Baby Yoda Lithophane

This has been my biggest resin print to date and I really wanted to push the printer to see what it could do.  I am blown away by the mid bending properties of Lithophanes and how, on a budget resin printer, I can make photorealistic 3D art.  

Amazing and definitely fits into "optical Illusion" territory.

Displacer Kitten and Displacer Beast - Thingiverse 4830184  / My Minifactory

Fellow Dragons Keep member Kat told me that her DM had recently gifted her a Displacer Kitten as a moving-in gift so I quickly sourced this super cute mini and an equally awesome displacer beast to represent the kitten when fully grown.

Displacer Kitten

Displacer Beast

Of course no birthday gift can come without a presentation gift box and my old 3D Printer sacrificed some of it's foam packaging for a custom box.

Displacer Beast Gift Box

Wednesday 15 May 2013

Optical Illusions in RPGs

In a previous post I wrote about the Droste Effect, a form of optical illusion using recursion, which provoked an exploration of other illusions, particular those of a physical or architectural nature. 

Now I'm sure everyone is familiar with Indiana Jones and the Last Crusade and remembers the final Grail test where Indy has to make "The Leap of Faith" out into the chasm to find a hidden walkway.  This is a good example of a forced perspective illusion, the walkway is painted in such a ways as to  render it invisible from the only perspective that the hero can have, the ledge.



This limits your options in a collaborative group scenario, as either requires you to bottle-neck the party or limit the number of viewers to force the illusion to work. However, perspective can also be used to make something visible (or at least legible) from only a single point of view. In otherwords an Anamorphic Perspective, the word itself being derived from the Greek words 'ana' meaning back or again, and 'morphe', meaning shape or form.

Anamorphic Perspective in Art History


One of the more famous paintings to demonstrate this trick was "The Ambassadors" (Hans Holbein the Younger 1553). In this we can clearly see a strange random grey shape which floats at the bottom center of the image.
The Ambassadors (Hans Holbein the Younger, 1553)
If the painting is viewed at an acute angle from the left side (as demonstrated above) the strange grey shape resolves into an image of a skull. 

Many art historians have come up with explanations as to its symbolism, which is unsurprising as the painting contains many cryptic clues as to the identity of the two sitters, although my favourite is that Holbein did it to show off his skill as a painter.

The painting hangs in London's National Gallery and well worth a visit, if you can't and want to learn more, the curators have put together a few nice videos to explain the painting's symbolism and how Holbein might have achieved the effect.

At the same time Erhand Schön a prolific woodcut designer from Nuremberg was using the technique to hide naughty pictures in his art.  This example is held by the British Library.
Jonah and The Whale (Erhard Schön, 1537) containing the anamorphic Squatting Peasant (highlighted in red)

More Modern Examples


One of my favourite modern exponents of the technique is Felice Varini who uses striking geometric shapes painted on the walls of rooms and even on the outside of buildings.

Rettangoli gialli concentrici senza angoli al suoo (Felice Varini, Switzerland, 1997)

Here's a great example from Brusspup, which uses a sliding glass door and coloured paper.


So how the heck do I use this in an RPG?

Anamorphic Illusions can be simulated in RPGs in one of two basic ways, either:

Room as presented to players
In Plan View - By presenting presenting the players with a map of a room (either as a handout or as a battlemap) in which are contained several prominent architectural features. 

In the example below it would something like:

"Beyond the door lies an undecorated and austere looking 100ft square room with no exits.  Against each wall stands a large statue which appears to be pointing with it's right hand outstretched at a series of large urns which stand in front of the northernmost statue.  Each urn appears to be sealed shut with wax and is large enough for a man to climb inside.  On the front of each urn is pasted a label adorned with strange eldritch symbols".

Room with solution (in red)
The solution (if you spotted my deliberate misdirection) is that the statues are not pointing at the urns at all.  They are in fact pointing to a floor tile (red square) which if smashed will reveal a secret under ground tunnel.

You could of course allow the party members to make copious spot hidden checks to determine the true target of the pointing statues.  If they cross the red square whilst traversing the room to reach the urns, their footsteps will cause an echo in the tunnel below.

Or you could just fill the urns with unspeakable horrors and watch the party dash across the room to their doom.  Your game your choice.


As a Handout - One of the simplest types of anamorphic uses layers which need to be positioned above one another to produce the effect.  Consider the three images below, trace these out onto some semi transparent paper (such as grease proof paper) or print them on OHP paper.  Tell your PC's that they have been written on the finest almost translucent animal skin or that they are etched onto sheets of glass.

Handout AHandout BHandout C

Message is revealed when
the images are combined
Individually they don't really much, but when combined together they read "This is a Hidden Message".

It's best to keep the handouts square, as you should let them spend some time puzzling over each one before they get them in the right orientation.

This is a massively oversimplified example for a fantasy game.  In a modern or future game glass and other transparent materials are common place and the handouts should seem matter of fact.

I've been toying with the idea of presenting my players with some DNA Chromatographs where the little blobs spell out a message when overlayed.  Luckily the extent of our knowledge of biology or medicine is limited to CSI Miami, so the science of chromatography shouldn't get in the way of a good reveal.

On a Serious Note... Dwarves and other little people


Whilst writing this I discovered a real world application of an associated technology to produce a similar effect.  Lenticulars have been atound for years, you see them on stickers, movie posters, postcards, anything where you want to show movement, animation or to reveal a hidden image.

The Spanish organisation, Anar Foundation, has recently produced a poster campaign which uses lenticular printing to reveal a hidden message including the telephone number of an anti-child abuse help-line.  The lenticular is arranged so that the message is only visible to children (or people of children's height) and not any adults (or potential abusers) who may be accompanying them.  A great idea and I'm sure you'll agree a worthy campaign.


This technique is of course something you could use in a delve of an old dwarven (or other half person) stronghold.  The original builders may have left messages to their kin in the walls which are only visible to persons of dwarvish height.  These could be anything from simple sign posts, elaborate trompe l'oeil vistas or warnings about the trap a bit further up the corridor.

Enjoy...

Friday 3 May 2013

The Droste Effect: Has anyone used it in a game?

After downloading Tiles of the Dead: Games Room (Crooked Staff Publishing), I'm now thinking about running a one session game devoted to the Droste Effect.
Packaging for Droste Cacao

What is the Droste Effect?

Simply put the Droste Effect is a particular form of recursion when an image appears within itself.  It is named after a Dutch brand of cocoa powder which used the effect in it's advertising but has been used by artists from M.C.Esher to Jan Van Eyck for hundreds of years. 


Scenarios which use a Droste Effect are largely going to be dependant on the exact characters in the game but everyone needs at least two things:

  • A Focus - This is essentially a portal to each level of recursion, deeper and deeper down the rabbit hole.  The floorplan I mentioned above has a typical RPG table (complete with character sheets) which acts as its focus, but this could just as easily be a photograph (or a woodcut) on a mantlepiece, a window or even the PC's own shadows cast in their torchlight. 

    Whatever you choose, as soon as the players notice the Droste Effect in the image then they should feel that the world has gone a bit wonky for a moment.  How long it takes for them to work out that this a'int Kansas anymore depends largely on how obvious you make the differences between realities or how quickly the next recursion happens.

  • A Pivot Point - The Droste Effect revolves around it's pivot.  Locate the pivot point within the scenario and the players just have to work out what the correct outcome is and "hey presto" the Droste Effect will resolve itself and the world resets with no lasting effects on the PCs.  Get it wrong and you need to find the focus again and enter the next level of recursion.

Some Scenario Ideas

Mirror, Mirror - A great way of introducing a Droste Effect into any game is to use a mirror as portal to a mirror universe.  PCs will find that adventures in a mirror universe will have a peculiar set of complications; backwards writing, driving on the opposite side of the road, guns with ejection ports on the other side throwing hot casings into your eyes, you can see where I'm going with this.

Evil Kirk - Throw the players off by replacing one of their PCs with an Evil version of themselves.  To make it harder for them to spot, just replace one of their personality traits with it's diametric opposite.  Your normally grumpy or pessimistic Dwarf, becomes cheerful and eternally optimistic, just see how long they can last before they drag him kicking and screaming back to where he came from.  The pivot for this could be that all the PCs have to become Evil for the Droste Effect to collapse.   A more sadistic DM would make sure that injuring your Evil counterparts had some sort of penalty like reflective damage.

Uppa, Groundhog Style - Whatever the genre, the groundhog day scenario forces the players to repeat their actions until they hit on the right solution (aka the pivot).  This could become tiresome for players until they work out what the pivot is, so make sure that you let them fast-forward through the non-relevant bits.  This is probably the closest to a traditional Droste Effect as each day is one level of recursion.

Everyone is Everyone Else - When the PCs encounter the Droste Effect, make each of them pass their character sheets to the player on their left.  They must now try to play the character in front of them in the style of the characters owner.  Best played in an established group where no-one takes themselves too seriously.  Each time they encounter the Droste Effect they pass their character sheets to the left until everyone has had a turn, the pivot for the scenario is simply that everyone must play everyone else until their original character sheets come around.  Of course once they work this out they will try to quickly resolve the Droste Effect by "Goal Hanging" so you make it harder by moving the focus around making it more of a treasure hunt.

One of our PCs is missing - Each time the PCs encounter the Droste Effect one of their number is missing and they will remain trapped in this Droste until they locate the missing PC.  You could rehash another meme (Final Destination), by making the missing PC die in interesting ways just as they are found, thereby triggering a new Droste Effect.  The pivot is that you must prevent the missing character from dying.

Have you tried it?


If you have any ideas, suggestions or experience of using the Droste Effect in your own games, feel free to comment below.

The Arnolfini Marriage
(Jan Van Eyck 1434)
close up of mirror, inscription reads
"Jan Van Eyck was there 1434"