Jack

Jack Dorsey, the billionaire founder of tech firms Twitter and Square, is still bullish on the world’s most valuable cryptocurrency.

Dorsey said in a tweet Tuesday evening that — out of the hundreds of virtual currencies in existence — the only one he currently holds is bitcoin.

Dorsey also promoted a social media game called “lightning torch,” where users add funds to a bitcoin payment and then send the “torch” along to another person so they can add funds and so on.

“Cool example of #BitcoinTwitter experimenting on the Lightning Network,” Dorsey said, before passing the “lightning torch” onto Elizabeth Stark, CEO of Lightning Labs, a blockchain company he has invested in.

The game is part of an effort to promote the so-called “Lightning Network,” an update to the bitcoin network that would work as an additional layer to the existing distributed ledger that underpins bitcoin. The upgrade would, in theory, make bitcoin transactions cheaper and faster.