BDOWN
fc = BUP * uvert + BDOWN * dvert + BRIGHT * rhori;
BUP * uvert + BDOWN * dvert, 1);
BDOWN * (dvert > 1), 1);
fc = BUP * uvert + BDOWN * dvert + BLEFT * lhori;
(spn == NULL ? 0 : BDOWN * bw) +
BRIGHT * rw + BUP * uw + BDOWN * dw, 1);
BHORIZ * rw + BUP * uw + BDOWN * dw, 1);
(spn == NULL ? 0 : BDOWN * bw) +