How to Smoothly Round the Corners of a Rectangular Fence?

[Oregonerd]

One way would be clever sketching on a single plane and rotating radius segments.

How to model a pair of handlebars?

You simply need to create one side and mirror the other. Try this: Draw a circle. Use the “move tool” to move and make copies of the circle using the (+). Move and rotate the circles in a half hazard arc. Then use the loft tool to loft from circle to circle. Also try this: draw a flat line with 2 lines and 2 arcs kinda like a handlebar. Using the move tool, move the anchor point to where the lines connect and rotate to make the flat line twist into 3d space.