Foreshortening 

Figure Drawing 

This image was drawn to show the effects of foreshortening of the human skeleton.
Drawing cuboids helps to define the volume that each limb takes up and also makes recognising foreshortening easier. 
Practise with foreshortening is recommended. 

Still Life - Composition 

The image above has been created to show finer points of composition. Using a more extreme angle, it is possible to see inside the mug and the way light and shadow is affected by the cylindrical form.

Scale is an issue here, and should be kept in check with pre-planning the image.