Grid vs no grid

Step 1 of his exercise will give you a sense of drawing with the left side and alternatively with the right side of your brain.

STEP 1. Draw two squares on two separate pages.

Draw a 4 x 4 grid on the first page and use this first reference photo (with the same square grid) and map out the intersecting points with objects and grid. 

Leave the other photo without a grid (below) for another day and just draw the vases by measuring by eye.

STEP 2. Re-visit all of the hatching and shading marks you have already played with

What you will determine from this exercise is the difference between drawing on the right side of the brain or using mainly the left. 

I don’t recommend left-side techniques like gridding and triangulation to people who are really keen on learning to draw by eye and develop that skill. Why?

Because once you give up training the right (the imagination, the visual perception, the translation of lines, shapes, spaces, proportions, values etc),  that skill just doesn't develop any further.