Chapter 1 - Tools of Geometry - 1-2 Points, Lines, and Planes - Practice and Problem-Solving Exercises - Page 16: 13

$\overset\longrightarrow{RS}$ $\overset\longrightarrow{RT}$ $\overset\longrightarrow{RW}$ $\overset\longrightarrow{ST}$ $\overset\longrightarrow{SW}$ $\overset\longrightarrow{TW}$ $\overset\longrightarrow{SR}$ $\overset\longrightarrow{TR}$ $\overset\longrightarrow{WR}$ $\overset\longrightarrow{TS}$ $\overset\longrightarrow{WS}$ $\overset\longrightarrow{WT}$

Each pair of endpoints can be used to identify a ray. Changing the order of the endpoints identifies a different ray since the ray continues in the direction of the endpoint on the right.