Using an ice cream maker add 1st soda to the frozen container base and run for 15-20 minutes until it is slushy.
Remove to a bowl and place in the freezer to keep cool.
Repeat with the remaining two sodas.
Meanwhile wet the rims of 4 chilled glasses and coat in purple sugar sprinkles.
Once you finish freezing the last soda, pour the slushy into the four glasses, filling about 1/3 full.
Remove the other two sodas from the freezer and mix up if needed.
Now pour each slushy soda layer into the glasses until filled. You should have three colored layers.
Top with a festive straw and serve immediately.