Rotamind

Rules

Rotamind shows twenty pairs of shapes. In each pair, the right shape is either the same as the left one, turned, or its mirror image, turned too: answer “Same” or “Mirror”.

• The clock starts with the first pair and stops at your twentieth answer.
• A wrong answer adds 3 seconds to your time; you move on to the next pair. At the end, each missed pair plays again: you see the shape turn.
• The shapes grow from 5 to 8 cells over the game, turned in steps of 45 degrees. Each pair is a mirror one time in two, drawn on its own, and no shape is symmetric: each pair has only one right answer.
• The daily challenge is the same for everyone, renewed at midnight (Paris time); only your first try of the day is ranked. The free run draws new shapes every game; your best time of the day counts.
• With a keyboard: F or left arrow for “Same”, J or right arrow for “Mirror”.
• Answers too fast or too even for a hand are kept but not ranked.

Mental rotation

In 1971, the psychologists Roger Shepard and Jacqueline Metzler showed two drawings of blocks side by side and asked whether they were the same object turned or its reflection: the time to answer grew with the angle, as if the object were being turned in the head. This is mental rotation.

Rotamind makes it a timed challenge, in two dimensions: twenty pairs, the same challenge for everyone every day. It is a game, not a medical test.