Jazz concert

Groupe Ma Valise in concert in a bar.
A figure has three dimensions. The draughtman must represent it on a sheet whith two dimensions Under a point of vue.The artist wants to catch a looking like portrait.
But peole always are moving. The draughtman must then light his so called grandmère neurone a long time enough so that a vue can allow calculate another one.
So after an while observing the pencil can be activated for an harvest of lines. This technique is one usable for all figures in movement.