Class discussion

Color Deducto

We began by playing Color Deducto, which most of you found to be easier thant regular Deducto. (See

What makes the M-heart-eight puzzle so challenging that even Lisa Simpson had trouble with it?

Institute professor Jerome Lettvin once said "Seeing and thinking are inseparable." Our visual system is susceptible to a variety of messages: (1) positional; (2) facial, e.g., texture, contrast of value, contrast of hue, translucency; (3) silhouette, e.g., orientation, size, shape; (4) dynamics, e.g., index, path, extent, speed; and (5) others, e.g., focus, stereo.

In order to inform, persuade, and stimulate (or fool, mislead, or fatigue), messages must have integrity, credibility and excite the observer.

Making the message available is sufficient for some applications. But for most applications, the message must be both available and easy to receive. In order to design a message which is distinct, reliable, and gets the attention of the observer, one must grade its degree of visual prominence. This is the means of determining whether or not the message is able to be perceive and decoded. It also has to have its proper place in the hierarchy of information, so that it gets the attention it deserves.

Congruence amongst messages can make messages easier to receive. Inconsistency amongst messages can lead to inhibition of the communication, or even, miscommunication.

Some people have visual deficiencies, such as color blindness. Others have "enhancements," such as synesthesia.

Hermann Grid

Parallel Lines

Adelson gray illusion


Reading inhibits color naming (it is harder to identify the color yellow when it is used to write the word green), but color naming doesn't inhibit reading (it isn't harder to read the word green when written in yellow). Reading doesn't inhibit color discrimination, but color discrimination inhibits reading.

Adelson's motion without movement

Find the right angles (from Gardner)


Cut each shape into to pieces that are identical


Trace the shape without crossing any lines twice and without lifting your virtual pencil

Diamond Sequence

What symbol goes in the blank space?

Square Grid

Divide the grid into two pieces such that they can be joined to make a square.

Paper Cut

Can this piece of paper be unfolded flat?


Fold the paper to make a book where the pages are sequenced as numbered. (You are allowed one cut, but the paper must remain whole.)

Double Cross

Cut the cross into five pieces such that they form two identical crosses.

Cross Squared

Cut the cross into four pieces such that they form a square.

Divide and Conquer

Divide the circle into four regions, each the same size and shape and each containing two stars.