- (Cube _ i j k _ _) = cube
- f = value_at fvs (i-1) j k
- b = value_at fvs (i+1) j k
- l = value_at fvs i (j-1) k
- r = value_at fvs i (j+1) k
- d = value_at fvs i j (k-1)
- t = value_at fvs i j (k+1)
- fl = value_at fvs (i-1) (j-1) k
- fr = value_at fvs (i-1) (j+1) k
- fd = value_at fvs (i-1) j (k-1)
- ft = value_at fvs (i-1) j (k+1)
- bl = value_at fvs (i+1) (j-1) k
- br = value_at fvs (i+1) (j+1) k
- bd = value_at fvs (i+1) j (k-1)
- bt = value_at fvs (i+1) j (k+1)
- ld = value_at fvs i (j-1) (k-1)
- lt = value_at fvs i (j-1) (k+1)
- rd = value_at fvs i (j+1) (k-1)
- rt = value_at fvs i (j+1) (k+1)
- fld = value_at fvs (i-1) (j-1) (k-1)
- flt = value_at fvs (i-1) (j-1) (k+1)
- frd = value_at fvs (i-1) (j+1) (k-1)
- frt = value_at fvs (i-1) (j+1) (k+1)
- bld = value_at fvs (i+1) (j-1) (k-1)
- blt = value_at fvs (i+1) (j-1) (k+1)
- brd = value_at fvs (i+1) (j+1) (k-1)
- brt = value_at fvs (i+1) (j+1) (k+1)
- int = value_at fvs i j k
+ expected = eval fvs $
+ (3/8)*I +
+ (1/12)*(F + R + L + B) +
+ (1/64)*(FT + RT + LT + BT) +
+ (7/48)*T +
+ (1/48)*D +
+ (1/96)*(FR + FL + BR + BL) +
+ (1/192)*(FD + RD + LD + BD)