turtles-own [
  infected
]

to setup
  clear-all
  crt num-turtles [
    set xcor random-xcor
    set ycor random-ycor
    set heading random 360
    make-well
  ]
  
  ask one-of turtles [
    make-sick
  ]
  
  reset-ticks
end

to go
  ask turtles [
    wiggle
    heal
    infect
  ]
  tick
end

to wiggle
  rt random-float wiggle-angle
  lt random-float wiggle-angle
  fd wiggle-distance
end

to heal
  ifelse infected = 1 [
    make-well  ;; this will set infected = 0
  ]
  [
    if infected > 0 [
    set infected infected - 1
    ]
  ]
end

to infect
  if infected > 0 [
    let doomed other turtles-here with [ infected = 0 ]
    if any? doomed [
      ask one-of doomed [ 
        make-sick
      ]
    ]

  ]
end

to make-sick
  set color yellow
  set infected days-infected
end

to make-well
  set color blue
  set infected 0
end