Workout

Warm up (500)
300 swim
200 kick

Set (700)
8 x 50 on :50
4 x 75 on 1:30 
...kick/drill/swim by 25 

Set (1200)
4 rounds
100 (3/4 catch-up drill)
2 x 50 sprint on 1:00
4 x 25 ez on :40

Set (600)
100 kick on 2:30
4 x 100 on 1:45
…descend 1-2, 3-4
4 x 25 variable on :45
   #1: hard/easy
   #2: easy/hard
   #3: all easy
   #4: all hard

Cool-down (200)
200 EZ choice