As a global cyberinfrastructure, the Internet makes authentic digital problem spaces like educational virtual environments (EVEs) available to a wide range of classrooms, schools and education systems operating under different circumstantial, practical, social and cultural conditions. And yet, if the makers and users of EVEs both have a hand in what can be initially achieved and subsequently repeated, then replication is not only a matter of precise repeatability but also specific variation. In this light, the study enlists one EVE in order to examine both classroom learning and educational research methodology. Two Singapore secondary school enactments of the "Quest Atlantis" Taiga curriculum are compared with one another and with previously published US enactments. Statistically significant learning gains precisely repeat Barab and colleagues' findings while classroom practices specifically vary from its design narratives. Descriptions of the progressive development of Singapore enactments illustrate a methodological tack for understanding continuity and change within Singapore classrooms and between Singapore and US classrooms as necessary functions of diversity. The juxtaposition of these analyses characterize tensions between replication and implementation fidelity and, in turn, frame EVEs as a tool for understanding and leveraging precise repeatability and specific variability of curricula. (Contains 2 tables.)