• ✓Steps arrive one at a time and the old one goes when the next comes — show the whole chain at once and it turns back into a paper sum
• ✓Every chain is proved whole-numbered, never negative, never above its ceiling, and always divides exactly (npm run verify:mindload)
• ✓No clock, because this measures holding rather than hurrying — unlike /games/speed-math, which teaches the speed tricks
• ✓The Kidsquare Rule: three slips in a row shortens the chain by one step, and says plainly that this is working memory at its edge, not bad arithmetic
• ✓A Thai voice reading each step aloud as it appearsplanned

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