The Knight's Puzzle

The Knight declared that as many as 575 squares could be marked off on his shield, with a rose at every corner.
How this result is achieved may be realized by reference to the accompanying diagram:

Join A, B, C, and D, and there are 66 squares of this size to be formed; the size A, E, F, G gives 48;
A, H, I, J, 32; B, K, L, M, 19; B, N, O, P, 10; B, Q, R, S, 4; E, T, F, C, 57; I, U, V, P, 33; H, W, X, J, 15; K, Y, Z, M, 3; E, a, b, D, 82; H, d, M, D, 56; H, e, f, G, 42; K, g, f, C, 32; N, h, z, F, 24; K, h, m, b, 14; K, O, S, D, 16; K, n, p, G, 10; K, q, r, J, 6; Q, t, p, C, 4; Q, u, r, i, 2.
The total number is thus 575.
These groups have been treated as if each of them represented a different sized square.
This is correct, with the one exception that the squares of the form B, N, O, P are exactly the same size as those of the form K, h, m, b

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Medieval Brain Teasers