Drawing as cognitive training - Vertical line

How to draw a straight vertical line

Stage 1

Take an A4 sheet paper and an HB pencil.
Use the paper as portrait layout
Vertically put three dots across the sheet. One at the top left, another in the left middle and the last one at the bottom left.
Keep the pencil at the first dot, look at the middle dot and draw the line without looking at pencil tip. The line drawn will be straight. Repeat the exercise from the middle point to the last one.
Repeat the exercise for five minutes from top to bottom t and bottom to top.

Stage 2

Repeat the exercise putting the pencil tip at first point and looking at the last point.
The long line drawn will be passing through the middle point and the line drawn will be straight.
Repeat the exercise for three minutes.
Stage 3

Draw a straight vertical line across the sheet without marking any point. The line drawn will be a long straight line.