diff --git a/benchmarks/plot_bench.py b/benchmarks/plot_bench.py
new file mode 100644
index 00000000..f4f61317
--- /dev/null
+++ b/benchmarks/plot_bench.py
@@ -0,0 +1,44 @@
+from glob import glob
+import pandas as pd
+import matplotlib.pyplot as plt
+
+bench_files = glob('stored_results/*')
+headers = ('File','Eval time (s)')
+
+benches = ['q2.lisp', 'fibonacci_tail.lisp', 'dec_cnt3.lisp',
+           'dec_cnt1.lisp', 'fibonacci.lisp', 'tak.lisp',
+           'dec_cnt2.lisp', 'insertionsort.lisp']
+
+data = []
+
+plt.figure(figsize=(10.0, 5.0)) # in inches!
+
+for bench in benches:
+    dict = {}
+    for file in bench_files:
+        file_info = file.split('benchresult')[1]
+        file_details = file_info.split('_')
+        df = pd.read_csv(file,index_col='File')
+        
+        date = file_details[0] + '-' + file_details[1] + '-' + file_details[2]
+
+        if (bench in df.index):
+            row = df.loc[bench]
+            dict.update({date : row[1]});
+        else:
+            print("missing data point ", bench, file )
+                        
+    lists = sorted(dict.items()) # sorted by key, return a list of tuples
+    x, y = zip(*lists) # unpack a list of pairs into two tuples
+    plt.plot(x, y, label=bench)
+
+
+lgd = plt.legend(loc='center left', bbox_to_anchor=(1, 0.5))
+ax = plt.gca()
+for tick in ax.get_xticklabels():
+    tick.set_rotation(45)
+plt.ylabel("Sec")
+plt.grid()
+plt.savefig('benchresults.png', dpi=600, bbox_extra_artists=(lgd,), bbox_inches='tight')     
+plt.yscale('log')
+plt.savefig('benchresults_log.png', dpi=600, bbox_extra_artists=(lgd,), bbox_inches='tight')     
diff --git a/benchmarks/stored_results/benchresult22_02_27_20_00_58 b/benchmarks/stored_results/benchresult22_02_27_20_00_58
deleted file mode 100644
index 23956e4b..00000000
--- a/benchmarks/stored_results/benchresult22_02_27_20_00_58
+++ /dev/null
@@ -1 +0,0 @@
-File, Load time (s), Eval time (s), GC avg time (us), GC min time (us), GC max time (us), GC invocations, GC least free
diff --git a/benchmarks/stored_results/benchresult22_07_11_09_42_55 b/benchmarks/stored_results/benchresult22_07_11_09_42_55
new file mode 100644
index 00000000..f84f5007
--- /dev/null
+++ b/benchmarks/stored_results/benchresult22_07_11_09_42_55
@@ -0,0 +1,9 @@
+File, Load time (s), Eval time (s), GC avg time (us), GC min time (us), GC max time (us), GC invocations, GC least free
+q2.lisp, 0.002300000, 1.308599948, 525.423706054, 300, 600, 59, 1920
+fibonacci_tail.lisp, 0.002799999, 0.005499999, 300.000000000, 300, 300, 1, 2047
+dec_cnt3.lisp, 0.002000000, 1.081699967, 453.333343505, 300, 500, 15, 1996
+dec_cnt1.lisp, 0.001500000, 3.051199913, 488.000000000, 300, 500, 100, 2014
+fibonacci.lisp, 0.001599999, 3.199199914, 493.617034912, 300, 500, 94, 1968
+tak.lisp, 0.002600000, 2.824199914, 537.931030273, 300, 600, 203, 1854
+dec_cnt2.lisp, 0.001500000, 2.371400117, 482.000000000, 300, 500, 100, 2014
+insertionsort.lisp, 0.004499999, 0.007199999, 300.000000000, 300, 300, 1, 2047
diff --git a/include/lbm_version.h b/include/lbm_version.h
index 243acd82..d70ddda6 100644
--- a/include/lbm_version.h
+++ b/include/lbm_version.h
@@ -29,6 +29,10 @@
 
 /*! \page changelog Changelog
 
+Jul 13 2022: Version 0.5.4
+  - Added function that lookups based on the second field in assoc structures.
+    Called it "cossa" as it is like assoc but backwards.
+
 Jul 4 2022: Version 0.5.4
   - Added possibility to partially apply closures. A partially applied closure
     is again a closure.
@@ -42,8 +46,8 @@ May 22 2022: Version 0.5.3
   - Fix evaluator bug in progn that made tail-call not fire properly when there
     is only one expr in the progn sequence.
 
-May 10 2022: Version 0.5.3 
- - symbols starting with "ext-" will be allocated into the extensions-list 
+May 10 2022: Version 0.5.3
+ - symbols starting with "ext-" will be allocated into the extensions-list
    and can on the VESC version of lispbm be dynamically bound to newly loaded
    extensions at runtime.
 
@@ -54,7 +58,7 @@ May 5 2022: Version 0.5.2
  - Line and column numbers associated with read errors.
  - More explanatory descriptions in error messages related to read errors.
 
-May 2 2022: Version 0.5.2 
+May 2 2022: Version 0.5.2
  - Performance tweaks to the evaluator. Small but positive effect.
 
 May 1 2022: Version 0.5.2
diff --git a/include/symrepr.h b/include/symrepr.h
index 030788f0..5817beb0 100644
--- a/include/symrepr.h
+++ b/include/symrepr.h
@@ -164,6 +164,7 @@
 #define SYM_ASSOC               0x148
 #define SYM_ACONS               0x149
 #define SYM_SET_ASSOC           0x14A
+#define SYM_COSSA               0x14B
 
 #define SYM_IS_FUNDAMENTAL      0x150
 
diff --git a/src/eval_cps.c b/src/eval_cps.c
index efcbc9c9..07e664f8 100644
--- a/src/eval_cps.c
+++ b/src/eval_cps.c
@@ -1851,8 +1851,6 @@ static inline void cont_closure_application_args(eval_context_t *ctx) {
     lbm_stack_drop(&ctx->K, 5);
     ctx->app_cont = true;
     ctx->r = closure;
-    //lbm_set_error_reason("Too few arguments.");
-    //error_ctx(lbm_enc_sym(SYM_EERROR));
   } else {
    sptr[2] = clo_env;
    sptr[3] = lbm_cdr(params);
diff --git a/src/fundamental.c b/src/fundamental.c
index 71354f0a..8f217aa5 100644
--- a/src/fundamental.c
+++ b/src/fundamental.c
@@ -650,6 +650,19 @@ lbm_value assoc_lookup(lbm_value key, lbm_value assoc) {
   return lbm_enc_sym(SYM_NO_MATCH);
 }
 
+lbm_value cossa_lookup(lbm_value key, lbm_value assoc) {
+  lbm_value curr = assoc;
+  while (lbm_type_of(curr) == LBM_TYPE_CONS) {
+    lbm_value c = lbm_ref_cell(curr)->car;
+    if (struct_eq(lbm_ref_cell(c)->cdr, key)) {
+      return lbm_ref_cell(c)->car;
+    }
+    curr = lbm_ref_cell(curr)->cdr;
+  }
+  return lbm_enc_sym(SYM_NO_MATCH);
+}
+
+
 lbm_value lbm_fundamental(lbm_value* args, lbm_uint nargs, lbm_value op) {
 
   lbm_uint result = lbm_enc_sym(SYM_EERROR);
@@ -881,6 +894,22 @@ lbm_value lbm_fundamental(lbm_value* args, lbm_uint nargs, lbm_value op) {
       } /* else error */
     }
   } break;
+  case SYM_COSSA: {
+    if (nargs == 2) {
+      if (lbm_is_list(args[0])) {
+        lbm_value r = cossa_lookup(args[1], args[0]);
+        if (lbm_is_symbol(r) &&
+            lbm_dec_sym(r) == SYM_NO_MATCH) {
+          result = lbm_enc_sym(SYM_NIL);
+        } else {
+          result = r;
+        }
+      } else if (lbm_is_symbol(args[0]) &&
+                 lbm_dec_sym(args[0]) == SYM_NIL) {
+        result = args[0]; /* nil */
+      } /* else error */
+    }
+  } break;
   case SYM_ACONS: {
     if (nargs == 3) {
       lbm_value keyval = lbm_cons(args[0], args[1]);
diff --git a/src/symrepr.c b/src/symrepr.c
index c4fafc3f..e4ffc113 100644
--- a/src/symrepr.c
+++ b/src/symrepr.c
@@ -157,6 +157,7 @@ special_sym const special_symbols[] =  {
   {"setix"          , SYM_SET_IX},
 
   {"assoc"          , SYM_ASSOC}, // lookup an association
+  {"cossa"          , SYM_COSSA}, // lookup an association "backwards"
   {"acons"          , SYM_ACONS}, // Add to alist
   {"setassoc"       , SYM_SET_ASSOC}, // Change association
 
diff --git a/tests/test_cossa_0.lisp b/tests/test_cossa_0.lisp
new file mode 100644
index 00000000..6eb4027c
--- /dev/null
+++ b/tests/test_cossa_0.lisp
@@ -0,0 +1,4 @@
+(define alist (list '(1 . a) '(2 . b) '(3 . c) '(4 . d)))
+
+(and (eq (cossa alist 'c) 3)
+     (eq (cossa alist 'a) 1))
diff --git a/tests/test_cossa_1.lisp b/tests/test_cossa_1.lisp
new file mode 100644
index 00000000..44b2ad06
--- /dev/null
+++ b/tests/test_cossa_1.lisp
@@ -0,0 +1,4 @@
+(define alist (list '(p . a) '(q . b) '(r . c) '(s . d)))
+
+(and (eq (cossa alist 'b) 'q)
+     (eq (cossa alist 'd) 's))
diff --git a/tests/test_cossa_2.lisp b/tests/test_cossa_2.lisp
new file mode 100644
index 00000000..ea7e166f
--- /dev/null
+++ b/tests/test_cossa_2.lisp
@@ -0,0 +1,7 @@
+(define alist (list '(p . a) '(q . b) '(r . c) '(s . d)))
+
+(setvar 'alist (acons 't 'e alist))
+
+(and (eq (cossa alist 'b) 'q)
+     (eq (cossa alist 'd) 's)
+     (eq (cossa alist 'e) 't))
diff --git a/tests/test_cossa_3.lisp b/tests/test_cossa_3.lisp
new file mode 100644
index 00000000..c9d718db
--- /dev/null
+++ b/tests/test_cossa_3.lisp
@@ -0,0 +1,6 @@
+(define alist (list '(1 . a) '(2 . b) '(3 . c) '(4 . d)))
+
+(setassoc 'alist 3 'e)
+
+(and (eq (cossa alist 'c) 3)
+     (eq (cossa alist 'a) 1))