If a closed string splits and its two parts later reconnect , its worldsheet will look like a single pipe splitting to two and then reconnecting , which also looks like a torus connected to two pipes -LRB- one representing the ingoing string , and the other -- the outgoing one -RRB- .

For example , if a closed string splits , its worldsheet will look like a single pipe splitting -LRB- or connected -RRB- to two pipes -LRB- often referred to as a pair of pants -- see drawing at right -RRB- .
