Boolean Logic Test

A 4 × 4 grid of keys. Tap the green key in the bottom left corner, and two patterns of lit keys follow one another, a second each. Then pick every key that fits the rule, and tap the green key again.

Six rules, one after the other, each explained before it starts: lit every time (AND), lit at least once (OR), never lit (NOR), dark at least once (NAND), lit an odd number of times (XOR) and an even number (XNOR). Each rule has six rounds, from 2 to 7 lit keys in each pattern: a point for each key you find that fits, a point off for each other key you pick.

The keys are random, but the rounds are the same size for everyone, so scores can be compared. You need to remember both patterns, then apply the rule to each key: the later rules are hard.