ATM
Hopcroft & Ullman's TM for {wcw | w in (a + b)^+}
a b 	// input alphabet
a b T B  // tape alphabet
1	// number of tapes
2	// number of tracks on tape 0
2	// tape 0 is 2-way infinite
[q1,B]	// initial state
[q9,B]	// the final state
[q1,B]  a+B  [q2,a]  a+T  r  // "a+B" means "a" on the top track, "B" on the lower track
[q1,B]  b+B  [q2,b]  b+T  r  // the single "r" means the tape head moves right
[q2,a]  a+B  [q2,a]  a+B  r
[q2,a]  b+B  [q2,a]  b+B  r
[q2,b]  a+B  [q2,b]  a+B  r
[q2,b]  b+B  [q2,b]  b+B  r
[q2,a]  c+B  [q3,a]  c+B  r
[q2,b]  c+B  [q3,b]  c+B  r
[q3,a]  a+T  [q3,a]  a+T  r
[q3,a]  b+T  [q3,a]  b+T  r
[q3,b]  a+T  [q3,b]  a+T  r
[q3,b]  b+T  [q3,b]  b+T  r
[q3,a]  a+B  [q4,B]  a+T  l
[q3,b]  b+B  [q4,B]  b+T  l
[q4,B]  a+T  [q4,B]  a+T  l
[q4,B]  b+T  [q4,B]  b+T  l
[q4,B]  c+B  [q5,B]  c+B  l
[q5,B]  a+B  [q6,B]  a+B  l
[q5,B]  b+B  [q6,B]  b+B  l
[q6,B]  a+B  [q6,B]  a+B  l
[q6,B]  b+B  [q6,B]  b+B  l
[q6,B]  a+T  [q1,B]  a+T  r
[q6,B]  b+T  [q1,B]  b+T  r
[q5,B]  a+T  [q7,B]  a+T  r
[q5,B]  b+T  [q7,B]  b+T  r
[q7,B]  c+B  [q8,B]  c+B  r
[q8,B]  a+T  [q8,B]  a+T  r
[q8,B]  b+T  [q8,B]  b+T  r
[q8,B]  B+B  [q9,B]  B+T  l
end