Arrows with orientation (V3 0 0 (-1)) render incorrectly

[jfearnley]

Arrows with orientation (V3 0 0 (-1)) incorrectly render with orientation (V3 0 0 1)

The following code should produce six arrows, but only five are drawn.

import Vis
import Linear

arrows = VisObjects [ Arrow (1, 10) (V3 1    0    0   ) white
                    , Arrow (1, 10) (V3 0    1    0   ) white
                    , Arrow (1, 10) (V3 0    0    1   ) white
                    , Arrow (1, 10) (V3 (-1) 0    0   ) white
                    , Arrow (1, 10) (V3 0    (-1) 0   ) white
                    , Arrow (1, 10) (V3 0    0    (-1)) white
                    ]

main = display defaultOpts arrows

Really nice library otherwise! I think I'll be using this quite a bit in the future.