diff --git a/thun/asm-dump.txt b/thun/asm-dump.txt
index 794d706..3aaa519 100644
--- a/thun/asm-dump.txt
+++ b/thun/asm-dump.txt
@@ -5,7 +5,7 @@ label(A),
 mov_imm(0, 0),
 store_word(0, 0, 0),
 mov_imm(0, 4096),
-mov_imm(1, S1),
+mov_imm(1, B2),
 mov_imm(2, 0),
 mov_imm(3, 0),
 store_word(2, 0, 0),
@@ -243,8 +243,47 @@ ior(9, 9, 6),
 store_word(9, 0, 0),
 do_offset(H),
 label(S1),
+symbol(S1),
+mov_imm(2, T1),
+do_offset(V1),
+label(T1),
+expr_cell(I1, 4),
+expr_cell(J, 0),
+label(U1),
+symbol(U1),
+mov_imm(2, W1),
+do_offset(V1),
+label(W1),
+expr_cell(R, 4),
+expr_cell(S, 0),
+label(X1),
+symbol(X1),
+mov_imm(2, Y1),
+do_offset(V1),
+label(Y1),
+expr_cell(J1, 4),
+expr_cell(J, 0),
+label(V1),
+mov_imm(7, 4),
+sub_imm(0, 0, 4),
+sub_imm(2, 2, 0),
+eq_offset(Z1),
+sub(2, 2, 0),
+and_imm(2, 2, 32767),
+label(Z1),
+sub_imm(7, 7, 0),
+eq_offset(A2),
+sub(7, 7, 0),
+and_imm(7, 7, 32767),
+label(A2),
+lsl_imm(2, 2, 15),
+ior(2, 2, 7),
+store_word(2, 0, 0),
+mov_imm(7, S),
+add_imm(7, 7, 4),
+do(7),
+label(B2),
 expr_cell(I1, 4),
 expr_cell(R, 4),
-expr_cell(J1, 4),
-expr_cell(J, 4),
+expr_cell(X1, 4),
 expr_cell(S, 0)].
\ No newline at end of file
diff --git a/thun/compiler.markII.pl b/thun/compiler.markII.pl
index 39e3bf9..1dd61ab 100644
--- a/thun/compiler.markII.pl
+++ b/thun/compiler.markII.pl
@@ -168,9 +168,21 @@ Mark II
     sub_base_merge_and_store(TEMP3, TEMP0, SP),  % Push first item onto stack.
     jump(Main),
 
+    definition(Unit, [New, Cons], DoDef, TOS),
+    definition(X, [Dup, I], DoDef, TOS),
+    definition(Swons, [Swap, Cons], DoDef, TOS),
+
+    label(DoDef),  % TOS points to body expr, set by definition.
+    asm(mov_imm(TEMP1, 4)),  % Used for linking to previous cell.
+    incr(SP),
+    sub_base_merge_and_store(TOS, TEMP1, SP),  % Push body expr onto stack.
+    asm(mov_imm(TEMP1, I)),  % Get address of I's machine code.
+    asm(add_imm(TEMP1, TEMP1, 4)),
+    asm(do(TEMP1)),
+
     % ======================================
     label(Expression),
-    dexpr([New, Dup, Swap, Cons, I])
+    dexpr([New, Dup, Swons, I])
 ]).
 
 
@@ -244,6 +256,12 @@ language.
 
 ⟐(definition(Name)) --> [label(Name), symbol(Name)].
 
+⟐(definition(Name, Body, DoDef, TEMP)) --> ⟐(definition(Name)),
+    [mov_imm(TEMP, BodyList),
+     do_offset(DoDef),
+     label(BodyList)],
+    dexpr(Body).
+
 ⟐(head_addr(Pair, HeadAddr)) --> [lsl_imm(HeadAddr, Pair, 2), asr_imm(HeadAddr, HeadAddr, 17)].
 
 ⟐(repeat_until(Condition, Body)) -->
diff --git a/thun/joy_asmii.bin b/thun/joy_asmii.bin
index 5e85ec7..9e6a2a1 100644
Binary files a/thun/joy_asmii.bin and b/thun/joy_asmii.bin differ