Draw a scalable house that the player should not drill into

Draw a scalable house that the player should not drill into. This is a sub-issue of #41.

Please create a global constant color of the part touching the ground for the win/lose checking.
An additional broken house would make the loose screen look cool.

In the code, there is a placeholder for drawing house(s) into the scene (might be not merged yet).
// todo add the houses here
// it is important to color houses differently
// because the status checking occurs based on color