XAllocNamedColor(dpy, DefaultColormap(dpy, screen), "black", &black, &dummy);
pmap = XCreateBitmapFromData(dpy, w, curs, 8, 8);
invisible = XCreatePixmapCursor(dpy, pmap, pmap, &black, &black, 0, 0);
XDefineCursor(dpy, w, invisible);
XAllocNamedColor(dpy, DefaultColormap(dpy, screen), "black", &black, &dummy);
pmap = XCreateBitmapFromData(dpy, w, curs, 8, 8);
invisible = XCreatePixmapCursor(dpy, pmap, pmap, &black, &black, 0, 0);
XDefineCursor(dpy, w, invisible);