Yes. Have three or four columns and place the values in the columns,
moving one column to the right occasionally as you go down the rows.

e.g. in the following two examples

  A
1  1
2  2
3  3
4  4
5  5
6  6

  A  B
1  1
2  2
3  3
4     4
5     5
6     6

In the first example, they're all the same colour. In the second,
they're two colours.

Look at Jon Peltier's blog for examples of using a Pivot chart to
achieve the same effect.

http://peltiertech.com/WordPress/2008/04/23/
  using-pivot-table-data-for-a-chart-with-a-dual-category-axis/