R2

Index

$\mathbb{R}^2$

$\mathbb{R}^2\setminus\text{point}$

$\mathbb{R}^2\setminus(2 \text{ points})$

This illustrates the fact that $\mathbb{R}^2$ is contractible. The contraction is just given by $h(t,(x,y))=(tx,ty)$.