The Transformation Deck
Drag the track to play the cards and watch the outline move. Then say where corner C finished.
This engine’s own main skill is Composing Transformations. It practises compose two visual transformations alongside it, and covers most of it rather than all.
The programme is “Flip in the line y = x”, then “Slide 2 right, 3 down”. Taking the cards one at a time, a flip in y = x SWAPS the two numbers: (x, y) becomes (y, x), and no sign changes at all; and then a slide adds the same pair of numbers to every corner: (x, y) becomes (x + 2, y − 3). Corner C starts at (-2, 3) and finishes at (5, -5). The order matters as much as the cards do: each card acts on wherever the shape has got to, not on where it started, so playing them the other way round can leave the shape somewhere else entirely.
- Step 1. Play it. Drag the fold track all the way across to play both cards, then scrub back and forth.
- Step 2. Where did it land?. Now the question: where does corner C finish?
What to say if they get stuck
- Scrub the track slowly, and back again. The pale outlines show every place the shape stopped.
- Follow corner C on its own rather than the whole shape - it leaves a dotted trail.
- a slide adds the same pair of numbers to every corner: (x, y) becomes (x + 2, y − 3).