Fill the 4-liter from the 7-liter bowl.
Fill the 3-liter from the 4-liter bowl.

You will have 3 liters left in the 7-liter,1 liter in the 4-liter and 3 in the 3-liter bowl. (Let us abbreviate that as 3,1,3)

Now pour from the 3-liter to the 7-liter bowl, and then pour the 1 liter left in the 4-liter bowl to the 3-liter bowl. (Now it looks like 6,0,1)

Now fill the 4 from the 7 (Now it looks like 2,4,1) 
Now fill the 3 from the 4 (Now it looks like 2,2,3) 

And you are done: 2, 2 and 3 liters!
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