The large squares represent X squared, and had two sides, blue and red, to determine whether it is positive or negative (blue = positive, red = negative). There is also the long rectangles that represent X, with the positive side being green and the negative red. The side length of X is the same side length of X squared, which makes sense because X multiplied by X equals X squared. The smallest square pieces represent the number 1. The colours are yellow for positive and red for negative. These are the basic pieces used in algebra tiles. Hope this helps
