Some embodiments include a pillar which contains semiconductor material, and which extends primarily along a first direction. A cross-section through the pillar along a second direction orthogonal to the first direction is through the semiconductor material and includes a lateral periphery of the pillar configured as three-sided shape. Some embodiments include an integrated assembly having a vertical stack of alternating first and second levels. The first levels include conductive structures and the second levels are insulative. Channel-material-pillars extend through the vertical stack. Each of the channel-material-pillars has a top-down cross-section which includes a lateral periphery configured as three-sided shape of an equilateral triangle with rounded vertices.