Each challenge is one shape, on its own. You study the target for a few seconds, it disappears, you redraw it freehand, and CYDI scores how close you got - then draws your attempt over the target so you can see where it drifted.
They are practice rounds: scored for real, and they change nothing in your game. No coins, no best score, no unlocks - so a challenge is playable whether or not you have reached its category in the Shape Challenge.
Pick a challenge
Draw a perfect circleOne unbroken curve, and it has to close exactly where it started.
Draw a perfect starFive arms of equal length, and ten straight edges to keep straight.
Draw a perfect heartTwo mirrored lobes, with the dip and the point on one centre line.