Make white layer: Combine all ingredients in a blender; blend until smooth.
Transfer to a bowl and refrigerate.
Make blue layer: In same blender (no need to rinse), combine all ingredients;
blend until smooth. Divide mixture among 6 ice pop molds. Freeze for 15
minutes. Rinse out and dry blender. Divide white layer mixture among pop
molds, pouring in carefully. Freeze 15 minutes.
Make red layer: Combine all ingredients; blend until smooth. You may need to
strain the mixture through a sieve to remove the seeds if using raspberries.
Divide among pop molds, pouring carefully over white layer. Place sticks in
molds and freeze until firm, at least 3 hours.