north side of the church have a blue background and shows predominantly scenes from the Old Testament, the windows on the south side of the church have a red background and shows a corresponding predominance of scenes of the New Testament, while the rose window motif that faces the sunset (west), symbolizes doomsday. The rose window's structural layout followed the design by cathedral architect Olaf Nordhagen, and the diameter is built up around an eightfold symmetry with the innermost parts proportioned such that the diameter is formed of 16 sheets. The window expresses how things move outward from Christ and converge back to him by doomsday. In the middle is a red gem, which symbolizes Christ. The rays outward represent yellow flames in a blue background. Angels are located at the end of each flame; those on the upper half are singing and playing while those on the lower half are six winged. In the outermost ring are the angels of the judgment. Between the angels of judgment are the symbols for the four Evangelists. In the upper left is the Matthew the Evangelist as an angel with a written scroll. In the upper right is John the Evangelist represented as an eagle. In the bottom right is Luke the Evangelist as an ox. In the bottom left is Mark the Evangelist as a lion. The painted glass in the window consists of over 10,000 pieces. The rose window was presented as a gift from the women of Norway for St. Olav's anniversary in 1930, it was completed the same year and is regarded as Kielland's masterpiece. Sculptures The sculptures on the west front are partially based on Maschius' drawings, on guesswork and on pure fantasy. Originally, the wall was framed with two side towers, and had a series of sculptures. The few of them that survived clearly show a French influence, particularly traceable to the cathedral in Reims. It is unknown how many rows of sculptures there originally were – only the bottom row survived the fires and decay of the late Middle Ages; the five remaining sculptures are in poor condition. These sculptures are now in the museum in the Archbishop's Palace. Work on the sculptures started in 1929. The sculptures depict both biblical and historical characters. The two lower rows of sculpture, proposed by Professor Oluf Kolsrud in 1928, are based on the engraving by Jacob Maschius.