The glossy white coffee cups are moving across the computer screen at a mind-blowing pace.
Forty-eight orders, and only two minutes to fill them all. Put cinnamon in one. Two cubes of sugar in another. Make the next one a double-chocolate. But don't let them spill.
Each month, millions of people from around the globe visit Lumosity.com  to try their hand at this "brain training" task and other challenges like it.
As Lumosity's customers - 60 million and growing - log on day after day, year after year since 2007, the information they generate from their play is collected into a giant repository of data.
It is the world's largest about how the human brain functions and changes over time. And in an unusual move, the company is allowing access to any academic researcher interested in studying it.
The dataset is so unique and its potential applications so limitless that more than 42 scientists from Harvard, Stanford, Duke and other institutions are now rushing to make use of the data in the hope that it will help them unlock some of the mysteries of the human brain.
Much of the initial work with Lumosity's data aims to confirm or debunk popularly accepted ideas based on past studies, such as how much sleep is needed for a brain to function optimally. But researchers hope that eventually they'll be able to find patterns or correlations in the numbers that could lead to new insights.
For instance, scientists might be able to use the IP addresses on customers' computers to create a map.
When overlaid with information from government agencies or other sources, they might show if certain neighbourhoods with toxic environments contribute to a higher risk of, say, early Parkinson's disease or dementia, says Richard Ivry of the University of California at Berkeley.
"Eventually you could begin to predict what can decrease and what can improve cognitive function," said Ivry, who chairs the psychology department and has written papers about the promise of big data.
The effectiveness of Lumosity's games on boosting brain power is a subject of much debate. One prominent paper concluded that while the games may yield improvements in the tasks at hand, they don't actually increase raw intelligence or unrelated skills.
Lumosity offers more than 40 multilevel games that are based strongly on recognised psychological tests. The nine-year-old, privately held company says it has made tens of millions off its subscription fees (typically US$14.95 a month).
Each interaction a user has with Lumosity - such as a response to an arithmetic question, for example, or a click that places chocolate in a customer's order in the coffee cup game - is logged in the company's database. Many of Lumosity's users also fill out survey information about basic demographics and lifestyle choices.
All of that data, minus identifiable information, is available for researchers to query.
Among the insights gleaned from the growing datasets is the intriguing finding that the optimal amount of sleep may be seven hours - not the popularly perceived eight or more, according to a paper co-published by Lumosity scientists and P. Murali Doraiswamy, a professor of psychiatry at the Duke University Medical Centre.
There were also some thought-provoking findings about ageing.
While scientists have long known that a person's cognitive functions decline as we age, the study was able to differentiate which skills you start to lose in what decade of life. In your 20s, for instance, spatial and working memory - related to how you visualise objects or your environment - start to decline. In your 30s, it's maths. And in your 50s, verbal fluency.