Aim
Working from a written program
Recording the steps in a program
Testing then modifying a faulty sequence

Resources
Interlocking 11 cm puzzle pieces (if available)
'Arrow' cards with Pixie commands
Paper copies of the puzzle pieces
Magnetic paper (for an improved version of the latter)

I discovered a child's interlocking foam 3D puzzle, which I turned into mats for the Pixie (similar to Roamer mats). The squares are just the right size to create a track on the board. The puzzle has different pictures on each square.

We made a track using the pieces, and the children took it in turn to program Pixie from one named place to another. Using the arrow cards, one child recorded the thoughts of their peers by blu-tacking the cards to a wedge so that we could all follow the program. If the program did not take the Pixie to where it was intended, we discussed the problems. Then we tried to correct the program using the cards.

Notes on the lesson
With support, the children were able to follow and read the written program and attempt to correct it. To aid this activity, I photographed the puzzle pieces and turned them into cards. Children could now select two pieces, one to start from and the other to move to. Blu-tacking the cards to the board and then rearranging them proved to be a little tricky for some children, so I re-created the cards using magnetic paper. These are easier to manipulate.