To understand prototyping time from a different angle, we plot the amount of time taken per prototype and find a median time between 17.5 and 20.5 weeks. For the first three prototypes, the time to completion grows slightly with each iteration. However, overall, the amount of time it takes to prototype stays close to consistent for each iteration, suggesting a "characteristic prototyping time" of about 19 weeks per prototype. Taking this characteristic prototyping time and multiplying it by 5 prototypes total results in 1.8 years. This number is below the 2.5 years median obtained from the workflow analysis for the overall prototyping period. The discrepancy is due to downtime between iterations, which was not included in the time for single prototypes. This downtime accounts for an additional six weeks on average per prototype. This time is often spent using that prototype for demonstrations and marketing as well as determining what to do for the next iteration.