Here's a sketch I found in my sketchbook that I see I didn't have posted here so I decided to present it here.

I normally work in blue pencil but this is one that I went back and did darker normal pencil over the blue lines to help define it. Normally I would shift all this to greyscale in Photoshop and you'd never know the difference, but I thought you might want to see the blue construction lines under the top dark pencil lines.

I love rough sketches from other artists like this. Show us your sketches.