Robot without legs!

My freshman year at college was quite interesting. Unlike previous years, our engineering class aka foundation class was completely transformed. UC's engineering department replaced the old program with a new class called Engineering Design and Thinking ENED. The course is divided into two semesters giving students a introduction to programming languages such as Python, LABVIEW, MATLAB and VBA. Also, we had two robot projects one each semester.

In the first semester we were suppose to build a robot from scratch using Lego Mind-storm Kit. The goal of the project was to build a prototype that could perform the following tasks: moving on black straight and curved line, moving on a dotted straight and curved line, crossing obstacles from 0.25 inches to 2 inches, lifting and dropping load. But here's a catch, we were not allowed to use wheels or anything that round or spherical. Therefore, we had to come up with ideas to make a complete leg structure that could not only work properly but also meet the speed requirements of the project.

We started with a structure that was similar to legs of a dog, but it didn't work out. The robot was moving on the same location.