The national Christmas tree on Independence Square (Maidan Nezalezhnosti) has come to symbolize the protests. When the protests began, the authorities blocked off a large chunk of the square and began to set up the tree.
Later, they beat student protesters with truncheons so that holiday preparations could proceed. During the next day's protests at St. Michael's Square, many people chanted, "Hang Yanik on the tree!" The police, however, secured the tree.
No longer. On Sunday, protesters liberated the tree, defying an order to stay away from the square. At first they planted flags on it. Later, they added posters. It is the most beautiful and original Christmas tree I have ever seen.
I can read some of the posters, but I need help from native Ukrainian speakers. I'll add translations to the captions as I get them.