B.ymin, B.ymax = B.ymin+Pv, B.ymax+Pv

		B.ymin, B.ymax = B.ymin+Pv, B.ymax+Pv; log(2, 'B down')

		B.ymin, B.ymax = B.ymin-Pv, B.ymax-Pv

		B.ymin, B.ymax = B.ymin-Pv, B.ymax-Pv; log(2, 'B up')

		A.ymin, A.ymax = A.ymin-Pv, A.ymax-Pv

		A.ymin, A.ymax = A.ymin-Pv, A.ymax-Pv; log(2, 'A up')

		A.ymin, A.ymax = A.ymin+Pv, A.ymax+Pv

		A.ymin, A.ymax = A.ymin+Pv, A.ymax+Pv; log(2, 'A down')

require 'log'

function log(stack_frame_index, obj)
  local info = debug.getinfo(stack_frame_index, 'Sl')
  love.filesystem.append('log', info.short_src..':'..info.currentline..': '..json.encode(obj)..'\n')
end