05. Draw the ground with the Pen tool and colour it a mid-green (#97C947) with no fill. Next, select the ground and apply an Inner Glow with Effect > Stylize > Inner Glow in #469923, with the opacity set to 75%, with Edge ticked. Using a separate layer for each, draw the ground’s other details — streets, parking lot, beach, and so on. Keep each object on a separate layer in an appropriate stacking order as this will make creating the diagram more logical and efficient.
06. One area might prove tricky: the beach. The transition from land to sand to water is more organic than metal and flat surfaces, so a regular Gradient wouldn’t work here. Use a Gradient Mesh (U) for this area: bend and twist the grid to create the contours. Then, using the Direct Select tool, select certain points and modify the colours accordingly.
07. We also need to emphasize the diagram’s 3D quality with a clean cut to the sides of the land and water. Using the Pen tool, create the sides and applied a Radial Gradient from the Gradient panel in green and blue. Next, tweak the corners using the Direct Select Tool (A) so they joined together perfectly. Last, I apply a Drop Shadow using Effect > Stylize > Drop Shadow in #000000, with the blending mode set to Multiply and the opacity set to 44%.