Thank you Landon.
If the leg of the chair is mounted horizontally it turns the chainsaw into a chopsaw.
This could be very handy for the processing of
firewood or for timber framing.
On a double swivel, you have a mitre saw.
............. edit....
Make a mobile chopsaw by attaching two pieces of 2x10 in an L-shape, as when building a corner.
Mount the leg of the chair onto the 2x10s and the saw would be mobile and could be carried to a big squared timber, held in place and used to make a nice square cut.