breed [cleaners cleaner]

to step ;; один шаг моделирования
if member? patch-here patches with [ dirt? ] ;; если текущий квадрат содержит пыль
[
    suck
]
if pcolor != red
[
    if count patches with [pcolor = red] > 0
    [
        face min-one-of (patches with [pcolor = red]) [distance-nowrap myself]
        fd 1
    ]
]
end

patches-own [ dirt? ]

to Setup
clear-all
ask patches
[
    ifelse random-float 10 < 1
    [ set-dirt true ]
    [ set-dirt false ]
]
create-cleaners 1
[
    setxy min-pxcor min-pycor
    set heading 90
    set color green
]
end

to go
if count patches with [pcolor = red] > 0
[
    ask cleaners [ step ]
    tick
]
end

to set-dirt [ val? ]
set dirt? val?
ifelse val?
    [ set pcolor red ]
    [ set pcolor 2 + (pxcor mod 2) + (pycor mod 2) ]
end

to suck
ask patch-here [ set-dirt false ]
end