This paper reports a work-in-progress that explores the use of 3D-printing for marker-based Tangible User Interfaces for use with smartphone-based eXtended Reality experiences. We have explored several ways to 3D-print matrix markers that are re-configurable so that the underlying values can change with user interaction. We have also applied 3D-printed markers to the development of a modular playset for exploring the Guia Fortress cultural heritage site in Macau SAR, China. We report some of the explorations of 3D-printed markers and describe the Virtual Guia Fortress playset.