Step 1: Parts list
a long length of 7/8 inch diameter sch. 40 pvc pipe
2 elbow couplings
1 threaded end cap adapter
1 4 way coupling
2 end caps
Oh and most importantly, you'll need the red thing of of this weird cone ball game from like the 60's
Step 2: Assembly
10 and 4 inch pieces for barrel
3(2x) and 6(2x) lengths for legs
The picture enclosed should explain things enough to get your mortar together.
Step 3: Your Done!
to fire, drop a single marshmallow down the barrel and strike the red thing on the ground.
the marshmallow should fly in a high arched trajectory like a real mortar before returning to earth.