ree')">+</button>
	<br>
	Interpolation points for the hack:
	<button type="button" onclick="dec('ips')">-</button>
	<input type="text" id="ips_input" value="1" onchange="change_ips();">
	<button type="button" onclick="inc('ips')">+</button>
	</form>
	<canvas id="both_canvas" width=640 height=640></canvas>
	<div style="text-align:center; padding-bottom:12pt;">
		<input type="radio" name="both" id="b_1" value="Add" /><label for="b_1">Add a point;</label> &nbsp;
		<input type="radio" name="both" id="b_2" check