In Kerobokan, there are long, idle hours for activity such as that. The hours are only broken by the visiting periods, six days a week, when friends and relatives of the prisoners squeeze into a tiled courtyard about half the size of a basketball court, jostling for space and sitting on reed mats on the hard ground. Stretched over the space, a canvas awning keeps out the worst of the noonday heat. It also traps the humid air in uncirculating stillness.

Another time I asked if, out in the prisoners' yard, with the rectangle of blue sky framed so starkly by the prison buildings, clouds become interesting. Sukumaran, who goes by the name Myu, thought about this for a while, as he did with most questions, before shaking his head. "Not clouds," he said. "Not really. But planes make you think. You see one now and again. I always think of that scene from The Unit." He went on to describe a complicated balloon-and-winch system, as seen in the television program, in which commandos are evacuated, by a kind of airborne slingshot contraption, from sticky situations in foreign places. There was something surreal, and a touch forlorn, about the fantasy. Later, he joked: "I really want one of those balloons. Maybe even a hot-air balloon would be enough. You wouldn't know where I could get one, would you?"

The prison nestles amid the narrow streets of Kerobokan - a bustling, ramshackle town not greatly touched by tourism - like a blank, monolithic temple, rimmed with barbed wire, all its activities turned inwards. Visitors, when finally they are granted access, receive a purple stamp on the wrist that allows them to leave. They bring food to the prison, and tissues are used as serviettes. Each day I visited, Sukumaran, who has a recurring nervous blink, would pick at these tissues as he talked, seemingly unaware of the action. He would tear them up into hundreds of tiny pieces, his fingers fidgeting methodically even as the conversation flowed gently. At the end of each visit, amid the food refuse and plastic water bottles, there would be a dense little mound of tissue confetti in a half-circle around where he had been sitting.

Sukumaran talks in a measured way, but it is clear his mind is racing. Andrew Chan, also on death row for the same offence, talks like a bag of firecrackers going off, and somehow seems more at home. Where Sukumaran is rangy, considered and thoughtful, Chan is compact, more spontaneous in his replies, something of a scrapper - quick with a cheeky smile, and always willing to offer analyses of other prisoners. "He's a puzzled individual," he said of one. "He's very puzzled. His life is a puzzle. And he doesn't know how to put the pieces together." Chan constantly riffs on themes in this manner, paraphrasing his own statements, throwing the words around, variation after variation, in a kind of comical running banter. He's something of a motor-mouth, in a larrikin way, and he has a few scars that make you wonder how often it's gotten him into trouble.

Chan and Sukumaran were arrested in April 2005, and charged with drug trafficking, along with seven other Australians. They came to be known collectively as the Bali Nine. Unlike Australia, where co-accused usually face trial together, in Indonesia the nine went through a series of separate trials and appeals in different combinations. All were found guilty and sentenced by judges of the District Court in February 2006. Sukumaran and Chan received the death penalty; the other seven, life imprisonment.

On each of Sukumaran and Chan's three appeals, that sentence has remained. For the seven others, several life sentences were reduced by the intermediate High Court to 20 years. On further appeal - by all except Renae Lawrence - to the Supreme Court, the sentences were increased to either life in prison or the death penalty. For a time in September 2006, when the Supreme Court handed down its decision, six were on death row. At that point, there was one more legal option: a final appeal to the Supreme Court, known as a Peninjauan Kembali, or PK. In their PK decided in 2007, three had their death penalties reduced to life imprisonment, leaving Sukumaran, Chan and Scott Rush on death row. Each has at least one legal option, the PK, still to be taken.