Question
I currently have a concrete L-shaped sidewalk running from the driveway to the house entrance.  I would love to make this more interesting by making it a curved walkway.  I have seen walkways that look like continuious swirled colored concrete.  What is this type of walkway called and is it possible to top the existing sidewalk with this?  Thank you.

Answer
I am not sure this is exactly what you mean but it seems like there are two questions.

One, yes you can create a curved sidewalk and get rid of all those hard lines but you must remove the old sidewalk and pour a new sidewalk using flexible concrete forms.
Use a hose to layout the curves first so you can decide what shape curves you like. You can kick the hose around to adjust it till you like the shape.

Second when you pour the new sidewalk you can add color to the concrete several different ways. You can add color to the mix using 'Integral Coloring ' agents. These are typically light tones that make the color something other than standard gray, like beige, buff, tan, black, light green, terracotta, red, etc. Or you can add a "Color Hardener" which is broadcast by hand onto the surface of fresh concrete before it cures. This can provide brilliant colors (all colors) and also makes the surface more resistant to scratching because the agent contains a lot of portland cement with a higher PSI curing. Both of these options are not recommended for the "do-it-yourselfer" and take lots of practice. Also the coloring agents are not typically available to the public sector and must be acquired through specialty stores. You will need to hire a concrete finisher who is familiar with and uses these products often. Also their are a lot of fly by night companies claiming to do good work but they really do bad work so make sure you see samples.
The last option for color is staining. You can stain with Acid stains which create permanent reactions in the concrete and color the surface or you can use porch and concrete stains available at most home stores, paint stores and hardware stores. However, these last types are a lot like paint and only barely penetrate the surface. They often wear off after a few years and need touch up much like paint.

Good Luck

Sean J Murphy, LA,ISA, LEED AP
Please check out my blogs and articles on landscape topics like this on my websites.
http://www.seanjmurphy.com
http://amenityarchitects.com