Shapes, patterns and repetition

Red, blue, red, blue, red … what comes next? Blue. You found the rule: change colour every time.

Patterns are everywhere: day and night, the days of the week, the stripes on a jumper, 2 4 6 8. Finding patterns is the first step in everything a computer «learns» — it looks for rules in masses of examples.

Harder patterns:

• ○ ○ △ ○ ○ △ ○ ○ … → next is △ (the rule: two circles, one triangle).
• 1, 2, 4, 8, … → next is 16 (the rule: double it).
• 5, 10, 15, … → 20 (the rule: add five).

Make a pattern of your own with blocks or sounds (clap clap stamp) and let a friend guess the rule. If your friend guesses wrong — was the pattern too short to be sure about?