fits_in
if (fits_in(curshape, pos + B_COLS)) {
if (!fits_in(curshape, pos))
if (fits_in(curshape, pos - 1))
if (fits_in(new, pos))
if (fits_in(curshape, pos + 1))
while (fits_in(curshape, pos + B_COLS)) {
if (fits_in(curshape, pos + B_COLS)) {
int fits_in(const struct shape *, int);