Shaple

Shaple is a short shape matching test credited to Ravi Parikh. One shape sits large at the top of the page, drawn at an angle with a different colour and pattern on each face, and three smaller shapes sit in a row underneath it. The instruction is a single line, choose the shape that matches, with a count of shapes left below it that started at five. The candidates disagree with the reference on colour, pattern, size and angle, so the only thing left to compare is the form. The page carries no date, no puzzle number and leaves nothing in the browser.

1. Look at the shape at the top of the page. It is drawn in perspective and each face carries its own colour and pattern.
2. Pick from the row underneath the one whose form is the same shape, ignoring how it is coloured, patterned, sized or turned.
3. Watch the line under the row. It counts the shapes you have left and started at five.

Five quick judgements about whether two objects are the same shape, with every other property deliberately scrambled to get in your way. Colour, pattern, size and angle all change between the reference and the candidates, so what the game is really asking is whether you can hold a form in your head while everything decorating it moves around. It is small, it is fast, and it asks nothing of you but the five calls.

The only live indicator on the page is the shapes left line under the instruction. There is no score, no clock and no attempt counter anywhere.

Core play

The page presents a single default puzzle: one large reference shape at the top and three candidate shapes beneath, with the instruction to “choose the shape that matches” and a “shapes left” counter that started at five.

• Colour and pattern are noise. The candidates are recoloured, repatterned, resized and turned relative to the reference, so the form is the only thing worth comparing.