The choice of colour is able to reflect the depth of the objects, and indicate the light source and the relationship between light and dark. The light source was set up in the top right corner of the drawing. In this case, I use gradient colours to show the graduate change of colour on the surface. And the light and dark of the colours create contrast and add details to the object. More specifically, the different gradation of the colour in terms of two adjacent objects will offer a clearer perception of the drawings than pure elevation photos present to us. 

After reading the reading, I understand that the elevation can only determine the transverse position of the objects, but fail to determine the distance from the object to the observation point. I make use of this characteristic of elevation and manipulating objects moving forward and backwards to create complexity.