The importance of ideation and sketch modeling in the design process.  

When you create something ultimately you have to source the stock material to bring it to reality.  During your initial ideation, you can create sketch models or mock-ups using cheap material.  The reasoning behind this... understanding the ergonomics of what you have created.  It is essential for young designers to understand that we can create in a virtual world, but we don't live in one.

Here is a few variations of a mobile air convection oven:

Ultimately, I decided I wanted to do my presentation with the "Dewalt-Tool Style", but I didn't want to 3D print or build an actual mock-up with fasteners, metal, and acrylic... so I went the sketch model route.  I used paper towel rolls, card stock, and poster board... I had some extra primer in a spray can, so I gave it a "finish" to give it a basic aesthetic.