  We study how forcing algebras give rise to ${\mathbb A}^1$-bundles and
${\mathbb A}^1$-torsors and how they are related to ${\mathbb A}^1$-patches. In
particular we discuss the affineness of torsors and how algebraic properties of
${\mathbb A}^1$-patches can be deduced from this property. This is in part a
survey article.
