data:image/png;base64,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

3010

1310

These magic numbers will have to be computed instead when we add more inputs later.

2data:image/png;base64,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It's somewhat artificial that we start with shape inputs for DRAW BRICK but have fixed values in DRAW ROW A and DRAW ROW B. Acknowledge that if students bring it up. The main reason we did this is that DRAW ROW B is easier if they can do the arithmetic instead of building algebraic expressions for the general case.3. The reason that the obvious attempt (with exactly half-size bricks at the ends) fails is that a row B has an extra cement gap -- six of them instead of five. Since we're using a length of 4 for a cement gap, the two end bricks must be reduced by 4/2 = 2 steps each, that is, to 13 instead of 30/2 = 15.