These fruit jellies look yummy. Here are the steps you need to do:
1- Wash some oranges, limes and lemons (or even grapefruits) and slice them into halves
2- Remove all the pulps from inside these fruits until only skin remains
3- Fill these fruit skins with prepared jelly (to prepare jelly follow the instructions on the packaging)
4- Put them in the fridge
5- After hardening, slice them into wedges
Another example is this brilliant watermelon jello shots. You can use sesame seeds for those little black dots.