This video from SimplySarc shows how to do that, but it doesn't work anymore in 1.9. In 1.9, it simply summons a item frame with a FallingSand entity on top. After a few seconds, the ItemFrame disappears and the FallingSand falls on the ground where it becomes solid.
Is there a way to prevent a specific FallingSand entity from becoming solid using the /summon command like in the video from SimplySarc?