Thiagarajan, S. (2015, April 3). By the numbers. The Thiagi group: Improving performance playfully. http://www.thiagi.com/archived-games/2015/2/25/by-the-numbers

Version also available in:

Thiagarajan, S., & Tagliati, T. (2011). Jolt 2—By the numbers. In Jolt! Activities to wake up and engage your participants (pp. 53-56). Pfeiffer.