Slice 2 lemons and 2 limes.
Juice the other 2 lemons and limes, which should give you about 1/2 cup juice.
In a large bowl, add sugar and boiling water. Stir to combine. Add in lemon/lime juice and 1 cup cold water.
In a popsicle mold, add a few slices of lemon and lime and fill with juice.
Add in popsicle sticks and freeze for 6+ hours.