Brown boxes - indicate positive values. Red boxes - indicate negative values. Green area - indicate where the boxes should go, and the condition they must fulfill. For example, if a green area of 2 has "3" on it, then the 2 boxes inside of it must sum to 3. Peach area - Operand square. For example, a "-" square will negate the value if positive, or ascribe the number shown in the area.