Several systems have a four-line staff alternating with two adjacent ledger lines. They are similar to the five-line staves (above), but they are slightly less visually dense (or “busy”), and require more ledger lines. They are also less likely to be confused with traditional notation. One system goes further with only three lines that alternate with three ledger lines per octave. Signs such as dynamic markings can be written in the space created by the ledger lines, even when multiple staves are stacked contiguously.