It is not yet dark, but the two girls sitting at a table in a Bogota bar flick on the lamp on their wooden table.
It is the signal to the bartender that they want a drink, in Colombia's first-ever bar for the deaf.
The Sin Palabras Cafe Sordo – No Words Deaf Cafe – is the first of its kind in the country, said Maria Fernanda Vanegas, one of three owners.
It is located in the trendy Chapinero neighbourhood of the Colombian capital, surrounded by heavy metal, gay and reggae joints.
"Its aim is for us, people who can hear, to adapt to the deaf, and not the other way round, which is always the case," said Vanegas.
The No Words cafe has large screens playing music videos with the lyrics in sign language, and a dance floor that pulses with music to dancers who cannot hear it.
The menus are also translated into sign language and there are games such as Jenga or dominos for customers to play.
Vanegas and her partners Cristian Melo and Jessica Mojica all have good hearing, but dreamed of opening a cafe for the more than 50,000 people in Bogota who do not.
Colombia has more than 455,000 deaf or hard of hearing people, according to the last census carried out in 2005.
People with normal hearing also frequent the bar, which is as noisy as any other in the capital. But the difference is that here, most of the talking is done with hands.
All six waiters at the bar are deaf too, and even though many of the clients do not know sign language, they manage to convey their orders with gestures or by writing them down.
The bar also features small cards showing the basics of sign language for drinkers interesting in expanding their repertoire.
There is no need to actually speak in the bar.
"Communicating with people with normal hearing can be a bit tricky at first because we don't understand them," said waiter Juan Carlos Villamil, 26. "But we get by somehow or other."
Some new clients are surprised at first, but they end up getting the hang of sign language, he said.
The idea for the cafe came to the owners when they saw a group of deaf people having a coffee, and asked them about their social lives. Now they want to open more bars like this across Colombia and elsewhere.
The bar opened on June 16, and with its exhibitions, story-telling and other cultural performances by hearing-impaired artists, it is already well on its way to becoming one of Bogota's more hip watering holes at weekends.