Those are great! I like the way you did them. We just finally finished ours too and we already got a foot of snow to test them out! It's funny, did you notice those mortar tubs now have a picture of ducks swimming in them on the label? Maybe they always did and I never noticed, LOL.
For anyone interested I do not have the plans, I just made it up as I went along, however I can give dimensions and any other info that people would find helpful.