I’ve seen this ‘toy’ elsewhere and after debugging Overview generation for foomatic I felt a quick break was in order so this morning I created WP Markerboard. It is a WordPress plugin that provides a “marker board” widget for visitors to play with. I built it using html5’s canvas element and jQuery.

An example can be seen below, try moving your mouse over the outlined box.

Being an html5 toy your browser must of course support the canvas element. For visitors without modern browsers the javascript fails gracefully.

The widget has four options, line color, line width, box width, and box height. Unfortunately canvas requires explicit dimensions, the default dimensions for Markerboard are 150px by 150px.

To install unzip the zip and ftp the resulting folder into your wp-contet/plugins/ directory. The plugin will then show up in WordPress’s list of plugins, active it, you may now add this widget to your sidebars.
Or simply install from wordpress’s add new plugin page as wp markerboard is hosted on wordpress.org’s plugin repository.
See WP Markerbaord on wordpress.org