The height of the leap was an illusion though. Nijinsky took five running steps from the middle of the stage and leapt through the window on the sixth step. The skirting board (base board) under the window was very low, giving the illusion that the leap was higher than it actually was.
The impression of a high jump was an illusion. Nijinsky took five steps forward from center stage before leaping through the window on the sixth step. The skirting board beneath the window was low, making it seem like he jumped higher than he did.