     @initParams    = [ virulence, mortalityRate, cureRate ] # to facilitate more sophisticated disease models
   fatal: ( organism, count ) ->
     p = @mortalityRate - organism.healthRatio() / @healthFactor
-    p > 0 and Math.random() <= p
+    p > 0 and random() <= p
   catches: (organism) ->
     p = @virulence - organism.healthRatio() / @healthFactor
-    p > 0 and Math.random() <= p
+    p > 0 and random() <= p
   spread: -> @
   cures: ( organism, count ) ->
     p = @cureRate + organism.healthRatio() / @healthFactor
-    p >= 1 or Math.random() <= p
+    p >= 1 or random() <= p

    start = @hp
    @hp += @gain()
    @hp -= @need()
    @hp = Math.min @hp, @health()
    @universe.change = true if start != @hp
  # number of times per baby that one can attempt to find it a cradle
  babyTries: -> @genes.babyTries[0]

pi  = Math.PI
qt  = pi / 2
tau = pi * 2

# import some functions
abs    = Math.abs
acos   = Math.acos
cos    = Math.cos
max    = Math.max
min    = Math.min
random = Math.random
round  = Math.round
sin    = Math.sin
sqrt   = Math.sqrt

# general handle on everything; keeps track of geometry of entities it contains
class Universe
