Quarter tone
A quarter tone increase is written with a half sharp
A quarter tone lowering by half a flat;
Input is done with the accidental menu or <alt-F11>
Immediate insertions with <ctrl-shift-#>, or <ctrl-shift-b>
Quartertones are played by MusiCAD as such, but are not taken into account in the sharps and flats automatic placement mechanism (in fact, a half sharp and a half flat are treated as a decorations)