A K'nex developer uses K'nex, a construction toy system, to create various structures, vehicles, and machines. They utilize the system's rods and connectors to build complex models, often based on engineering and architectural principles. Their work involves careful planning and design, understanding the components' interconnections, and troubleshooting any structural issues. They might also customize their creations with additional K'nex parts like gears, wheels, or pulleys. Besides building, a K'nex developer may also engage in teaching others how to use K'nex, creating instructions for models, or even developing new K'nex kits. Their work can be both recreational and educational.