⌂ Setting multiple time signatures at the start of a bar

Create a compound time signature for irregular meters.

Function \irregularMeter accepts the same arguments as function \compoundMeter; it also produces the same visual appearance of the time signature elements. However, it doesn't insert a plus sign between the (top-level) elements but rather a small horizontal space. Additionally, it doesn't change the timing, which means that it is still necessary to insert proper \time commands, to say \omit Timing.TimeSignature before the first \time command in the section with irregular meters, and \undo \omit Timing.TimeSignature after this section.