What is ironic about the sculptures? Why do you think King (or Red) includes this story? shawshank redemption

From what I read, the sculptures serve as distractions. Andy asked for a rock hammer to create stone sculptures. It is his legitimate excuse of acquiring the rock hammer which he also used to chip away the wall of his prison cell until it created a huge hole where Andy escaped.

The sculptures lend credence to Andy's request and the guards' believe that Andy is settling in prison life.