Coding classes in West Lothian

The heap is imaginary. The ground is a grid of 161 by 161 squares, each holding a column of grains. A grain is dropped at a tipping point and then obeys one rule: if a neighbouring square is at least two grains lower, it slides to the lowest such neighbour, and keeps going until no step down is that steep. Real spoil settles at a natural slope called the angle of repose; the rule builds the same idea into the grid. The learner drops 40,000 grains, first all at one point and then shared among five points in a row, and prints the heights.

The results match the idea in the record. Tipping from one place builds one cone whose sides settle at exactly the slope the rule allows, about 2 grains per square. Tipping from five places far enough apart builds five lobes, each about 36 grains high with shallow saddles between. Bring the points closer and the lobes merge into a single ridge with only slight bumps. The shape of the heap is written in the tipping plan, even though no line of code mentions lobes.

Then the learner looks harder and finds a surprise. The single heap reaches 30 squares from its centre along the grid lines but only about 21 squares along the diagonals: it is shaped like a diamond, not a circle. A real heap tipped from one point is roughly round. The diamond comes from the model letting grains slide only north, south, east or west, a grid artefact, and fixing it means adding diagonal moves with the right distances. The learner also finds that late grains travel much further, about 20 squares on average against 4 or 5 at the start, because they must run down a much larger slope.

A model that looks right can still be wrong in shape, and catching that is a reason for West Lothian teenagers to keep learning to code in 2026. The longer argument is in why teenagers should still learn to code in 2026.