FUNCTION scannert(x,y,distance)
scanner(x, y) = distance    ` set the distance TO current location

` scan left
gridvar = grid(x-1, y)
scanvar = scanner(x-1, y)
IF scanvar < distance AND gridvar = 0 THEN scannert(x-1, y, distance + 1.0)

` scan right
gridvar = grid(x+1, y)
scanvar = scanner(x+1, y)
IF scanvar < distance AND gridvar = 0 THEN scannert(x+1, y, distance + 1.0)

` scan up
gridvar = grid(x, y-1)
scanvar = scanner(x, y-1)
IF scanvar < distance AND gridvar = 0 THEN scannert(x, y-1, distance + 1.0)

` scan down
gridvar = grid(x, y+1)
scanvar = scanner(x, y+1)
IF scanvar < distance AND gridvar = 0 THEN scannert(x, y-1, distance + 1.0)

endfunction