This is for the Scene part of the contest.

Step 1: Grid

The size of the grid is 12 inches by 12 inches.

Step 2: Cave Boundaries

I used squares and enlarged them, each are 1/8 of an inch thick. The Top and Bottom are both 12" by 12". The three sides, are each 12" wide and and 6" tall.

Step 3: Adding a Little Depth

I created wedges and lined them along the edges to add some features to the base template. The two wedges in the back are a bit taller and have more width to them than the rest to add the "end of this cave" thought.

Step 4: The "trench" or Small River

To create the "Trench" or small area where a river or stream to go was used with two Roof pieces, one on the bottom and one flipped upside down to take out a small chunk out of the to be "trench". After it was taken out I kept it's base height but had it go 12" wide and 12" long. Afterwards I centered it on the base.

Step 5: Stalagmite and Stalactite Creation

I tried using different pieces but I ended up only using Paraboloids for the creation. I stretched them taller/shorter, wider/thinner, until I felt they were the right shape. I always used more than one Paraboloid in each stalagmite and stalactite.

Step 6: Placing Stalagmites and Stalactites

I put them all around so that they could fill in the most space but not get in the way of each other. They were placed randomly but just a note to say, don't leave big open areas in the design.

Step 7: Creation of the "bats"

For the bat's, it was tough. The head is a roof, two pyramids, two spheres that were brought down to shape by eyeballing it, and the "nose" is two thin cones tilted in all sorts of ways, again, it was eyeballed so it's up to you on how well it looks in your design. The body was simple, a stretched sphere length wise and a cone tilted inside to make a small tail. Lastly the wings, three wedges tilted into each other (I flattened the tips of the wings but that is optional because they will be hard to see in the end design). Before you start placing them, shrink them down to a reasonable size you see fit.

Step 8: Setting the Scene

I placed the bats where I saw would be most natural, don't spread them too much because then you might lose track of one or two and miss it.

Step 9: Final Product

Combine every piece together except the bats, so you can see them against the cave and not lose them.

Step 10: Minor Tweaks

The first small change I made was tilt the bats in different directions so it looked more realistic. The second was change the background to the lightest brown.