Two survey teams map the same space, but each uses its own slanted axes, its own basis.
Between the two surveys a machine moves every point: in ordinary standard coordinates it sends to .
North logged each point before the move, in North coordinates. South needs each point after the move, in South coordinates. Every step here is linear, so a single matrix does the whole conversion: if is a point's North coordinate vector, then is the moved point's South coordinate vector.
Task: write north_to_south(B, D, M) returning as a list of rows, every entry rounded to 4 decimal places.
B[k] is North's basis vector and D[k] is South's , each given as a list of numbers.M is an matrix given as a list of rows.