Alternative Ways of Obtaining Experimental Designs

1. Find previously created incomplete block designs. For example, the various editions of Cochran and Cox's Experimental Design contain multiple incomplete block designs. And, there are many, many designs freely available on the internet.
2. 'By hand' (i.e., learning and applying the mathematical techniques used for creating incomplete block designs). Generally it is not possible to do this unless you have postgraduate qualifications in mathematics.
3. Hire a consultant with expertise in this area. Generally, most consultants with such expertise will work in a maths department.
4. Use software.