grid_size, arc_pos, radius, diameter, focus_pos)
arc = makeArc(grid_size, arc_pos, radius, diameter, focus_pos, ...)
</pre>

<h2>Description</h2>

<p><code>makeArc</code> creates a binary map of an arc within a two-dimensional grid. The arc position is denoted by 1's in the matrix with 0's elsewhere. The arc is found using the mid-point circle algorithm, and is simply connected so that any grid point on the arc will have at most 2 neighbours.</p>

<p>The midpoint of the arc is set by <code>arc_pos</code>. T