Merge pull request #33 from lf-lang/line

Adding more track examples created by Aditya Krishnan (@the-systematic-chaos)

Author: the-systematic-chaos

.gitignore

@@ -64,3 +64,6 @@ include/
 # pico setup script location
 pico/
 lf-pico-solutions/
+
+# Temporary files by mdbook
+book/

src/Line.md

@@ -2,9 +2,19 @@
 
 The goal of this exercise is to program the Pololu robot in LF to perform track and line following, where the robot detects a line or track and follows it until it reaches the end.
 
-For this lab, you will need a suitable line like the one here (made using black ducktape and a white foam board):
-
-<img src="img/Track.jpeg">
+For this lab, you will need a suitable line like the ones below, made using black poster chart paper (cut in the shape of the track) or black ducktape on white foam boards:
+
+<table>
+<tr>
+<td><img src="img/Track_1.jpg"  alt="1" width = 360px ></td>
+<td><img src="img/Track_2.jpg" alt="2" width = 360px></td>
+</tr> 
+<tr>
+<td><img src="img/Track_3_4.jpg" alt="3" width = 360px></td>
+<td><img src="img/Track_Example.jpg" alt="4" width = 360px>
+</td>
+</tr>
+</table>
 
 ## 9.1 Prelab