Left white column from top to bottom, w1, w2 Second white column from top to bottom w3,w4 Left+right+up+down=lrud w1[l],w4[r],w1[d],w4[d+r] ,w1[u],w4[u],w1[d],w4[d], w1[l+d],w4[u],w2[l],w4[d], w1[u],w3[r],w2[d],w4[d], w2[u],w3[r],w1[u],w3[d], w1[r],w2[d],w3[u]