The photo below is a screen capture from a YouTube video about an older gentleman who gave his antique attic layout to a kind friend, however I cannot find the link at present or remember all the details. I believe this layout is now in a museum of some sort.
This meandering track plan reminds me of old amusement park "Fun House" dark ride track plans. I like the way the crossovers are used and feel inspired to use elements from this old layout for perhaps a charming Christmas layout. So I figured I'd post it in hopes it inspires others, especially for use with smaller O27 equipment with short locos and short rollingstock, on tight curves. I gather GarGraves flex track would be the best choice for the custom curves but bending GarGraves to even O27 curves is a little tricky, and frustrating. And I cannot figure the angle of those many crossovers or the radius of the curves, but guess the 45 degree O27 crossovers and curves would work with a little fudging. Even On30 would be good here.
Take care, Joe.