This lesson requires simple materials which you can see in the photo below. I like Crayola watercolor markers.
The pathway starts with two watercolor marker lines creating a "channel" within which students will draw and design their dots, using either warm or cool crayons.
Notice that the marker lines are either warm or cool and all but the very center of dots are the opposite (warm/cool).
Once the dots are designed, kids use a paintbrush and clear water to draw the watercolor marker into the pathway and the background. This is a good opportunity to talk about using just the tip of the brush and which direction to draw out the water. I like to have them paint the pathway quickly with plain water before drawing the watercolor color into the water.
When all is dry, students can join their pathways to create a whole collaborative network of paths.