def render():
    global terrain
    for l in range(len(terrain)):
        for c in range(bits):
            fill_rect(c*10+140,l*10+1,10,10,colors[0])
            if terrain[l]>>(bits-1-c) & 1:
                for d in ((1,0),(0,1),(-1,0),(0,-1)):
                    if 0 <= l + d[0] <= len(terrain) - 1 and 0 <= c + d[1] <= bits - 1 and not terrain[l + d[0]]>>(bits-1-(c+d[1])) & 1:
                        fill_rect(c*10+140+9*(d[1]==1),l*10+1+9*(d[0]==1),1+9*(d[1]==0),1+9*(d[0]==0),colors[1])