Put the summary of the bug you're having here

What I expected to happen was I would put in the sand and the coal wait a couple of minutes and ther would be glass.
Describe what you thought should happen here

*What actually happened was I put in the sand and when I went to put the coal in I could not even select the box, and when I went to remove the sand I could not do that. So what I had to do was break the furnace to get my sand back and tried it again, the same thing happened again. *
Describe what happened here

Steps to Reproduce:
1. Place the furnace
2. Tap it to use it
3. Place the sand where it's supposed to go
4. Try to place the coal (you can't)
5. Try to take out the sand (you can't)
6. Break the furnace to get the sand back