Referring to his Late Nudes, a series of paintings he began in 1994, Karel Appel said, “all that freedom that I won after fifty years of painting—freedom and technique, color and design—is then suddenly concentrated in the form of a nude.” Appel’s males and females don’t recline in reverie. His figures are upright and confrontational. Brushwork is aggressive, and the colors garrulous, kinetic. We get the impression these figures could move abruptly, at any moment. —E.C.