Artists are not human photocopiers. They make art for a reason, and try to share their ideas and visions with others. Artists spend quite a bit of time observing the world around them. They ponder things, people, politics, nature, mathematics, science, and religion. They observe color, texture, contrast, and emotion. Some artists do think in visual terms. They might want to do a painting that shows the beauty of the landscape or the interesting face of a person. Some art explores formal qualities of the medium, showing the hardness of stone or the vibrancy of a color. Art can express emotion, from joy and love to anger and despair. Some art refers to abstract ideas, such as a mathematical sequence or pattern.