• ✓Idea: the Wisconsin card sort — set-shifting
• ✓Every dealt card sends colour, shape and count to three DIFFERENT piles, so every answer is informative
• ✓Proved by npm run verify:switch before it reaches a screen
• ✓A miss prints what it just ruled out, instead of only saying no
• ✓EQ: three misses in a row buys a breath, then the rule is simply told to you once
• ✓An end-of-round line comparing how fast you spotted the switch with your own last roundplanned

✓ = done · ☐ = planned. Every game is built one step at a time like this.