When this cylinder is viewed from one end, we see a true circle.
As the cylinder is tilted away from us, the circle becomes an ellipse.
In an isometric projection, a circle appears as an ellipse.
The three steps for constructing an ellipse in isometric projection.
Step 1 – Draw the isometric square with equal sides to contain the ellipse.
Step 2 – Mark the center of each side of the isometric square.
Step 3 – Draw the ellipse in four parts, using the center marks as guides.
Try sketching below picture in isometric projection using plain paper.