A dot pattern is of the form: uv, where the digit u is the increment number of dots to light up horizontally, 1 <= u <= 9, and the digit v is the increment number of dots to light up vertically, 1 <= v <= 9. For example, a dot pattern of 34 means to light up every third dot horizontally and every fourth dot vertically. If uv is negative, then the dots are erased instead of turned on. 200 is interpreted the same as 211, that is, every dot is lit.