An IM set to keep you moving (and with lots of Freestyle).
20 X 100 SCY or SCM
Swim this set all the way through with no breaks. Legal turns throughout!
#1-12 are FRIM (IM except that you substitute Freestyle for Butterfly) on a sendoff that gives you 15-20 seconds rest. This sendoff is "X."
#13-16 are FRIM on X minus :05 sendoff (take 5 seconds off your original sendoff)
#17-20 are Freestyle on X minus :10 sendoff (take 10 seconds off your original sendoff)
To spice it up a bit, try IM on the first 12 X 100…FRIM on the next set of 4 X 100…and Freestyle on the final 4 X 10.
Alternate 1 X 100 IM and 1 X 100 FRIM for the first 16 X 100.
Swim the set as 20 X 125, adding a length of Backstroke, Breaststroke, or Freestyle.