Designing and printing cameras involves a lot of outright failures, tweaking and fine-tuning, feature by feature, until the final camera design is printable, functional, and elegant. This small basket of failures from my pre-Kickstarter design for Flyer has grown to overflow a large 52 gallon trash bin. Your PayPal donation of $1 or more per camera helps me keep designing and printing cameras for everyone to print and use (use Other, the form does not have a $1 option).
Remember, failure is not final. You learn something with each failure, and each iteration brings you closer to success.
(Donations are not tax-deductible)