请帮我解释解释这个vb代码的意思答:Picture1.ForeColor = RGB(icolor, icolor * Rnd, icolor * (1 - Rnd))Picture1.DrawWidth = a Picture1.ForeColor = RGB(icolor, icolor * Rnd, icolor * (1 - Rnd))Picture1.Cls movepoint x1, y1, d1 movepoint x2, y2, d2 movepoint x3, y3, d3 movepoint x4, y4, d4...