CAD - Drawing a slotted rotor

There is no audio on this video. Here is a description of the drawing steps:

• Draw the outer circle
• Draw one rectangular notch
• Use Transform - Polar Array Copy to make 11 copies of the rectangle, rotating each copy 30 degrees about the Z axis (ie 0,0,30)
• Select all, then convert all to polylines (CTRL+A, then CTRL+P)
• Select all again, then use Edit - Break at Intersections
• Select the parts of the shape to keep, then use Edit - Join
• Select the unwanted parts, then delete them (is easiest to select all, then CTRL+click on the shape to keep, to deselect it)