Rotate and Reflect
Use the polygon tool to make a polygon of your choice.
Rotate:
Plot a point near your polygon.
Click on the rotate tool (in the 'red dot-line-blue dot' icon).
Click on your polygon, then your point, then enter an angle of rotation.
Choose a factor of 360. Repeat as many times as necessary to complete a full turn!
Experiment with moving the points of your polygon, or the center of rotation.
Reflect:
Use the line tool to draw a line near your polygon, possibly even intersecting your polygon.
Click on the reflect tool (that's the 'red dot-line-blue dot' tool).
Click on your polygon, then the line.
Experiment with moving your polygon and/or the line of reflection.
Experiment by having more than one line of reflection.
Design:
Right click on your polygon, then use the menu at the top right to change colour/opacity.