Block-Based Programming

A programming paradigm where users create code by selecting and connecting visual blocks that snap together like puzzle pieces, rather than typing text-based syntax. Each block represents a programming construct such as a loop, conditional, variable assignment, or function call. Block-based programming environments like Scratch, Blockly, MakeCode, and AppInventor are widely used in K-12 computer science education because they eliminate syntax errors and let learners focus on computational concepts. However, their inherently visual and mouse-centric design creates significant accessibility barriers for students with visual impairments, who cannot see the blocks or use drag-and-drop interactions. Making block-based programming accessible requires alternative interaction mechanisms (keyboard navigation) and output channels (screen reader descriptions) while ideally maintaining the same platform so sighted and blind students can collaborate.