The Sketch dataset contains over 20,000 sketches evenly distributed across 250 object categories. The object categories in this dataset are based on the following criteria:

• Exhaustive: These categories exhaustively cover most objects that are frequently encountered in everyday life.
• Recognizable: These categories can be recognized from their shape alone, independent of context.
• Specific: These categories are specific enough to have relatively few visual representations. “Animal” or “Musical Instrument” are not good object categories because they have many subcategories.