Clear the table

From a script to a skill

Step 4's program only worked for one ball at one position. Real robots face a new scene every time, so this step reshuffles the balls on every run. Hard-coded coordinates won't survive.

Robust manipulation code follows a loop that roboticists call sense → plan → act → verify:

1. Sense: ask the world where things are (world.balls()).
2. Plan: compute the pre-grasp, grasp and place poses from those measurements.
3. Act: run the phases.
4. Verify: did gripper.close() return True? If not, back off, re-sense (the ball may have been nudged) and try again, up to a limit.

Wrap Step 4 in a function:

def pick_and_place(name) -> bool:
    ...

Then call it for each ball.

Stacking

The cup fills up. Three balls fit on the floor and the fourth sits on top, so release a little higher than before. That way a new ball never lands on a finger.

Your task

Get all four balls into the cup. For a bonus, drop them in rainbow order: red, yellow, green, blue.

The layout changes on every run, so press Run a few times to make sure your program really generalises.