"The curtain of night came upon us while we were riding our bikes home." Which figurative term is being used here?

The following excerpts that illustrate darl's and cash's points of view from william faulkner's as i lay dying: from darl: tull's wagon stands beside the spring, hitched to the rail, the reins wrapped about the seat stanchion. in the wagon bed are two chairs. jewel stops at the spring and takes the gourd from the willow branch and drinks. i pass him and mount the path, beginning to hear cash's saw. when i reach the top he has quit sawing. standing in a litter of chips, he is fitting two of the boards together. between the shadow spaces they are yellow as gold, like soft gold, bearing on their flanks in smooth undulations the marks of the adze blade: a good carpenter, cash is. he holds the two planks on the trestle, fitted along the edges in a quarter of the finished box. he kneels and squints along the edge of them, then he lowers them and takes up the adze. a good carpenter. addie bundren could not want a better one, better box to lie in. it will give her confidence and comfort. i go on to the house, followed by the chuck. chuck. chuck.of the adze.from cash: i made it on the bevel.there is more surface for the nails to grip.there is twice the gripping-surface to each seam.the water will have to seep into it on a slant. water moves easiest up and down or straight across.in a house people are upright two thirds of the time. so the seams and joints are made up-and-down. because the stress is up-and-down.in a bed where people lie down all the time, the joints and seams are made sideways, because the stress is sideways.except.a body is not square like a crosstie.animal magnetism.the animal magnetism of a dead body makes the stress come slanting, so the seams and joints of a coffin are made on a bevel.compare how the two narrators tell the story of addie bundren's impending death. is either narrator reliable? explain what the reader learns about each narrator. be sure to use specific details from the text to support your answer.