Ex 22
Revert "Ex 22"

This reverts commit b14bebdecf8aeaba55d3f228e591abc80e9fc9bb.
Revert "Revert "Ex 22""

This reverts commit d26d06f412ab8946e14896b3f9d3b63372ada03e.
Ex 23
Ex 24
Ex 25
Ex 25
Ex 26
Ex 27
Ex 27a
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Ex 30
Ex 31
Ex 32