Algodoo

I appreciate the effort, but there are some improvements I have to point out.

Many of the parts look improperly positioned that creates an uneven (artistic) balance. Use the grid tool to create a better balance and to center parts.
You can make text by making a box. Hover the cursor into the "Text" option and type the desired text at the box. I would recommend making the resolution at least 128 px by using the resolution slider.
I wouldn't recommend using the colors on the top left corner (or as I'd like to call, "basic" colors) and use the HSVA color slides (or the color picker above the sliders). In any and every object, uncheck the "Draw Borders" checkmark, found below the HSVA sliders.
The wheels should have controls. If you hover into the dark cyan box and click it, you are required to select a key (you can click it again to cancel). If you press a key and play the scene, you can control the object by using the axle.

Simulation frequency makes things act more realistic the more hertz you add, at the cost of computer power.
It isn't necessary to change an object's material just to find the right color. Again, use the HSVA sliders and/or the color picker box to find the right color.