In a Lagos classroom, Samuel Anyaele is teaching aspiring software developers - even if they don't own a laptop.
They're learning how to code using their mobile phones.
''In the environment where we live in there are more people with access to mobile phones than PCs, so by teaching them how to code on their mobile phones we are effectively giving them a tool to work whether they have a PC or not.''
Job opportunities are scarce in Africa's most populous country.
Two thirds of people aged 15 to 34 are either unemployed or under-employed.
Coding skills are seen by many young Nigerians as a way to earn money from clients based anywhere in the world.
One of Anyaele's students is Chinonso Okafar.
"There was no light and my laptop was down so I had to like move those folders into my phone."
He now builds websites and says using his phone means he can keep working for his clients when the electricity cuts out.
According to Anyaele, a lot of people want to learn tech skills but don't have the resources.
In some schools, he says, students are still writing codes on paper.
His is one of many companies that have sprung up to teach Nigerians how to code.
Anyaele runs free classes for beginners and charges $210 for courses aimed at professionals.
His classroom is in Yaba, a Lagos suburb commonly referred to as Nigeria's Silicon Valley.
It's a place where software developers dream of making it big.
Last year's $200m acquisition of Nigerian fintech firm Paystack by tech giant Stripe, and the $1 billion valuation of local payments company Flutterwave, have shown just what is possible.