table.canvas { }

table.canvas td.right_top { width:15px; height:15px; background-image:url('/images/canvas/right_top.gif'); }
table.canvas td.left_top { width:15px; height:15px; background-image:url('/images/canvas/left_top.gif'); }
table.canvas td.right_bottom { width:15px; height:15px; background-image:url('/images/canvas/right_bottom.gif'); }
table.canvas td.left_bottom { width:15px; height:15px; background-image:url('/images/canvas/left_bottom.gif'); }

table.canvas td.hor { background-image:url('/images/canvas/hor.gif'); }
table.canvas td.vert { background-image:url('/images/canvas/vert.gif'); }