Add water to juice to equal one cup. Heat liquid in microwave one minute.
Add jello to hot liquid.....
Stir until dissolved.
Pour dissolved liquid jello into can with pineapple.
Fill to the top.
Let set until firm, at least 24 hours.
Use a knife to run around rim of inside of can to help jello to slide out. This could have used more time. The idea is for it to be firm enough to cut into slices. It still tasted really good!