In brief
The Test Lab has one index for ideas and working demonstrations. A registry tells the index what each item is, how to display it and whether it has a page of its own. The project status report counts lab work separately from accepted article and graphic work.
Two layouts can test the same route
The calculator-link demonstration compares a compact link with a larger card. Each opens the converter with the pyramid already selected. That keeps the destination and the calculation fixed while the demonstration compares how much room each layout takes near the top of a narrow screen. The link and card can be tried side by side before a layout is adopted across the articles.
A demonstration has its own checks
Another lab page plots Petrie's four reconstructed side differences separately from the probable error of his mean. Its plotted values and internal links were checked on release. The lab can show a clearer way to present that distinction while the published study remains the place to read the full evidence and its limits.
The checks establish that visitors can use the demonstrations and follow their links. Adoption still requires a decision about which treatment to carry into the main site.