Christian Theodor Weinlig (July 25, 1780 – March 7, 1842) was a German music teacher, composer, and choir conductor, active in Dresden and Leipzig.
He chose a piece, generally something of Mozart's, drew attention to its construction, relative length and balance of sections, principal modulations, number and quality of themes, and general character of the movement.
Then he set the task: you shall write about so many bars, divide into so many sections with modulations to correspond so and so, the themes shall be so many, and of such and such a character.
Similarly he would set contrapuntal exercises, canons, fugues — he analysed an example minutely and then gave simple directions how I was to go to work.
With infinite kindness he would put his finger on some defective bit and explain the why and wherefore of the alterations he thought desirable.