Hi Dave, that spur gear plug-in that Ralf has the link to above is definitely the easiest way.

You install those files into the \commands sub-folder in MoI and then makes a new command available called "SpurGearProfile", which you can launch by setting up a keyboard shortcut with that command name on it.

But it is also possible to manually draw a gear without too much trouble - the main thing you do for that is to draw one tooth and then use Transform / Array / Circular to replicate it.

So for example starting with these 2 curves:



Use Transform / Array / Circular to replicate the box:



Then select all those curves and run Construct / Boolean / Union to fuse them together:




Another technique for making some customized patterns like this is to first draw in a polygon (Draw curve / Polygon) with as many sides in it to match how many elements you want in the final result. That then gives you a nice segment that you can snap on to and know that you can replicate that piece to make the full pattern.

That looks like this, starting with the polygon:



So note the segment indicated in red above - I used that segment as a snapping guide to draw this new curve:



Now that curve can be replicated using Transform / Array / Circular to make the pattern:



Then select all those pieces and use Edit/Join to glue them together into one curve.

- Michael