Landis witness Simon Davis resumed testimony that began Tuesday, offering more of his analysis of the machines, the process and the lab workers involved in Landis' positive test.

Much of the testimony from Davis, and rebuttal witness J. Thomas Brenna, was focused on the software used to produce the results and the manual regeneration of those numbers.

Davis said the software was so unreliable, it was impossible to trust any results.

"What we're looking at is very expensive, rather large random number generators," Davis said.

But Brenna testified there were good scientific reasons for every maneuver the lab technicians performed during the manual regeneration.

"It was easy to see because they were doing the same thing every time," said Brenna, an expert in the kind of testing done on Landis' urine. "It was very mechanical."

During cross-examination by the U.S. Anti-Doping Agency, Davis acknowledged the photo he produced Tuesday of a machine in the French lab with huge magnetic lifting rings sitting on it — a breach Davis said could cause huge errors in the tests — wasn't the one used in the Landis testing.

"It's not that it would change results of the case, but it shows a complete lack of knowledge of the instrument," Davis said.

The testimony was a clear shift from Landis' cross-examination Tuesday, during which USADA dredged up the Greg LeMond affair.

LeMond's revelations of sexual abuse and potential witness tampering turned this hearing into a melodrama, and the questioning veered way off the scientific facts that many presumed would decide this case. For instance, attorneys asked Landis about his decision to wear all black — when he'd been sporting a yellow tie on all other days — on the day of LeMond's testimony.

"Nothing good could come out of that day," Landis said.

Brenna was one of USADA's first witnesses when the nine-day hearing began last week.

Today, he wore a yellow tie.

"But just to make it clear, the only symbolism in this yellow tie is that my daughters picked it out," Brenna said.