A patchwork of protesters are trying to topple Thailand's government. They include supporters of the main opposition Democrat Party, ultra-royalist heirs of the "Yellow Shirt" movement and individuals united by their hatred of exiled former Prime Minister Thaksin Shinawatra.
Here are sketches of some of the main forces threatening the government of Prime Minister Yingluck Shinawatra, Thaksin's younger sister, and also of the pro-Thaksin "Red Shirts".
1) The electoral base of the Democrat Party
The main group of protesters is led by Suthep Thaugsuban, a deputy prime minister when the Democrats were in power. He calls for Yingluck's departure and the creation of an unelected "People's Council".
Suthep resigned from his party before protests escalated.
The Democrats have traditionally drawn support from the Bangkok-based elite -- officials, judges, the military and elements close to the Royal Palace -- who see Thaksin and his "Red Shirt" supporters as a threat to the monarchy and their own place at the top of the hierarchy.
They have not won a national election in 20 years, but enjoy strong support in Bangkok and the southern heartlands.
Party leader Abhisit Vejjajiva, who was prime minister from 2008 to 2011, has shied away from centre stage as the protests have intensified.
2. The ultra-royalist heirs of the "Yellow Shirts"
The People's Alliance for Democracy (PAD) is a royalist movement better known as the "Yellow Shirts". Their mass protests precipitated a coup against Thaksin in 2006, and helped oust two pro-Thaksin governments in 2008.
But since then the PAD has lost much of its influence. Its leader, media tycoon Sondhi Limthongkul, has not called for demonstrations -- experts speculate that is perhaps because it would violate the terms of his bail for his role in the occupation of Bangkok's airports in 2008.
Despite this, the crowd includes many former "Yellow" supporters including groups of ultra-royalists. They deny formal affiliation with the PAD but are headed by former "Yellow Shirt" leaders or are close to them.
"Many of these protesters are recycled Yellow Shirts" said Paul Chambers, a researcher at the University of Chiang Mai. "They are arch-royalists."
These groups include the Student and People Network to Reform Thailand, which led the brief occupation of the army headquarters, and also the People's Army against the Thaksin Regime -- some of whom would like to see a return to absolute monarchy.
Behind these groups stands the Dharma Army, a Buddhist organisation which provides free food to the protesters -- as it once did for the Yellow Shirts.
3. Individuals united by their hatred of Thaksin
A number of other more marginal groups have coalesced into an anti-Thaksin coalition.
For example, hundreds of young students from vocational schools in Bangkok have formed a group called "Vocational Help the Nation". Some wear black shirts and are acting as security for the protests.
4. The "Red Shirts"
In the opposing camp, the "Red Shirts" mainly draw support from the disaffected rural masses and urbanites from the north and northeast of Thailand. They showed their support for the government by camping for a week in a stadium in Bangkok.
But after peaking at some 70,000 people Saturday, their leaders appealed for protesters to go home to prevent further clashes with anti-government demonstrators after they suffered fatalities.
The Red Shirts, who do not challenge the monarchy, are Thaksin's main supporters.
They played a key role in the electoral victory in 2011 of the Puea Thai party, which brought Yingluck to power and allowed her to continue her brother's policies favouring the poorest -- which drew accusations of populism.
In 2010 some 100,000 Reds occupied the centre of Bangkok for two months to demand the resignation of Abhisit, before being dispersed by an army assault which killed 90 people and injured 1,900.