USING: arrays fry kernel math math.functions math.ranges
sequences sequences.extras ;
IN: lamps

: <lamps> ( -- seq )
    100 t <array> ;

: <people> ( -- seq )
    100 [1,b] >array ;

: toggle ( ? -- ? )
    not ;

: toggle? ( person-index lamp-index -- ? )·
    1 + swap divisor? ;

: toggle-switches ( n lamps -- )
    [ toggle? [ toggle ] when ] with map-index! drop ;

: do-switching ( -- lamps )
    <people> <lamps> [ '[ _ toggle-switches ] each ] keep ;