changed</span> <span class='op'>=</span> <span class='id identifier rubyid_sprite'>sprite</span><span class='lbracket'>[</span><span class='symbol'>:on_mouse_changed</span><span class='rbracket'>]</span>  <span class='kw'>if</span> <span class='id identifier rubyid_sprite'>sprite</span><span class='lbracket'>[</span><span class='symbol'>:on_mouse_changed</span><span class='rbracket'>]</span>
  <span class='ivar'>@on_mouse_up</span>      <span class='op'>=</span> <span class='id identifier rubyid_sprite'>spr