Published in ACM Interactions, Adding Reinforced Corners: Designing Interactive Technologies for Children with Disabilities discusses the need to add a fourth element to Resnick’s approach of "low floors, high ceilings and wide walls." These guidelines address context-based individual differences such as accommodating factors at the start of the games (beginners, intermediary, advanced levels), complexity of tasks and availability of individuals preferences. The idea is to add "ramps" of access to expand "low floors" by integrating tactile and auditory interactions; and adding "tall ladders" or "scafolds" to allow for expanded multi-modal avenues. The reinforced corners concept argues for the development of “extra” built-in support and attention into interactive technologies aiming to “push the boundaries of the walls, and expand opportunities at the lowest threshold and/or ceiling.”
Alper, M., Hourcade, J. P., & Gilutz, S. (2012). Adding reinforced corners: designing interactive technologies for children with disabilities. interactions, 19(6), 72-75.