Simple Future Tense: The artists<em> will create</em> a new painting <em>tomorrow</em>. (At one particular time in the future, this will happen).
Future Progressive Tense: The artists <em>will be creating</em> a new painting when he arrives. (The action of<em> creating</em> will begin before he arrives and <em>will be in</em> <em>progress</em> at a particular time in the future.)
Future Perfect Tense: The artists<em> will </em>already <em>have created</em> a new painting when he arrives. (First the artists will finish creating. Later he will arrive.)
Future Perfect Progressive Tense: The artists <em>will have been creating</em> a new painting by the time he arrives. (Event in progress before another event in the future.)
Perfect, he can’t actually hear her so he believes she is playing beautifully. This is the same thing as her practicing, he can’t actually hear her so she gets away with making mistakes.