Some make reference to those who leave graffiti on a surface as artists. The height of the wainscot all depends around the look the homeowner or decorator is attempting to achieve. Homeowners pour concrete driveways, patios and walkways outside of their homes.
As a geologic entity, marble features a much more restrictive definition: a metamorphic, highly crystalline carbonate rock that may be either highly calcitic (calcium)or dolomitic (magnesium). Structurae [en]: Hare's Hill Road Bridge (1869). Once these are already approved from the buyer (unless that's you), you can proceed and source materials and tools you may need. If the graffiti remains, move onto the next cleaning method.
Remember this as you embark in your first bricklaying journey. Proper planning prevents poor performance.