I've made an hourglass, and I'm quite satisfied with the final result (at least when compared to my own standards). Either way, criticism is appreciated.

(Also shading the sand as it builds up or flows down properly was slightly painful. Mirroring the hourglass properly for the 2nd half of the animation was also quite time-consuming, since I couldn't simply flip everything horizontally and get away with it - for example, the light source would've looked like it teleported. There might still be something I've overlooked, I don't know.)