diff --git a/pp/bench.py b/pp/bench.py
new file mode 100755
index 0000000..49f5cb0
--- /dev/null
+++ b/pp/bench.py
@@ -0,0 +1,227 @@
+#!/usr/bin/env python3
+'''
+A wee utility that I use to benchmark katas
+author: github.com/tmck-code
+
+usage:
+
+func_groups = [
+    [f1,f2],
+    [f3,f4,f5],
+    [f6],
+]
+tests = [
+    ( (arg1, arg2), {}, result1, ),
+    ( (arg3, arg4), {}, result2, ),
+]
+
+bench.bench(
+    tests=tests,
+    func_groups=func_groups,
+    n=100_000,
+    sort=('BENCH_SORT' in os.environ)
+)
+'''
+
+from collections import Counter, namedtuple
+from functools import lru_cache, wraps
+from itertools import chain, repeat
+import operator
+import pickle
+import time, sys, os
+from typing import Callable, Any
+import statistics
+
+from pp import pp
+
+Test = namedtuple('Test', 'args kwargs expected n')
+class NoExpectation:
+    'Denotes that a test/benchmark has no expected result (i.e. just benchmark it)'
+
+def set_function_module(func):
+    'Set the module of a function'
+    if func.__module__ != '__main__':
+        return
+    module = sys.modules[func.__module__]
+    if hasattr(module, '__file__'):
+        # if the function is defined in the main module, set the module to the filename
+        func.__module__ = os.path.basename(str(module.__file__)).split('.')[0]
+    else:
+        # if the module is not a file, set the module to the current directory
+        func.__module__ = os.path.basename(os.getcwd())
+
+@lru_cache
+def _load_serialised_args(serialised_args):
+    return pickle.loads(serialised_args)
+
+def timeit_func(func, args, kwargs, expected: object = NoExpectation, n: int = 10_000):
+    'Time a function with arguments and return the result, whether it is correct, and the times'
+
+    if os.environ.get('DEBUG'):
+        pp.ppd({'func': func, 'args': args, 'kwargs': kwargs, 'expected': expected, 'n': n})
+
+    start, times = 0, Counter()
+    # some functions may modify the input arguments, so a new copy is needed for every test
+    # "pickle" is used instead of "deepcopy" as it's much faster
+    args_ser = pickle.dumps(args)
+    # ensure that the function module is meaningful (replace it if it's just "__main__")
+    set_function_module(func)
+    for _ in range(n):
+        try:
+            start = time.time()
+            func(*_load_serialised_args(args_ser), **kwargs)
+        except Exception:
+            pass
+        finally:
+            times[time.time()-start] += 1
+    try:
+        result = func(*pickle.loads(args_ser), **kwargs)
+    except Exception as e:
+        result = e
+    return result, expected is NoExpectation or result == expected, times
+
+def _sum_times(times: Counter) -> float:
+    'sum the values*counts in a Counter'
+    return sum(map(operator.mul, *zip(*times.items())))
+
+def _avg_times(times: Counter) -> float:
+    return _sum_times(times) / times.total()
+
+def _median_times(times: Counter) -> float:
+    return statistics.median(list(times.elements()))
+
+TEST_STATUS = {
+    False: pp.ps('fail', 'red'),
+    True:  pp.ps('pass', 'green'),
+}
+TRUNCATE = 40
+
+def _truncate(s: str, n: int=TRUNCATE) -> str:
+    'Truncate a string to n characters'
+    if len(s) <= n:
+        return s
+    return s[:n-10] + '...' + str(s)[-10:]
+
+def _format_time(i: float) -> str:
+    '''
+    Format a time in seconds to a human-readable string, rounding to the nearest unit
+    e.g. 0.0000001 -> "100 ns"
+    Uses chars from the "mathematical italic small" unicode block for the units
+    '''
+    unit = 's'
+    for u in ('s ', '𝑚s', '𝜇s', '𝑛s'):
+        if i >= 1:
+            unit = u
+            break
+        i = i*10**3
+    return f'{i:7.03f} {unit}'
+
+RECORD_SEP = '│'
+BORDER_SEP = '─'
+HEADER_SEP = '┆'
+BORDER_END, BORDER_PATTERN = '★', '-⎽__⎽-⎻⎺⎺⎻'
+
+def gen_border():
+    w = os.get_terminal_size().columns
+    n = int(w/len(BORDER_PATTERN))
+    r = max(int(n%len(BORDER_PATTERN)/2)-1, 0)
+    b = (f'{BORDER_END}{" "*r}{BORDER_PATTERN*n}{" "*r}{BORDER_END}'
+        f'\n{BORDER_SEP*w}')
+    return b
+
+
+def _print_header(s: str, test: Test) -> None:
+    'Print the result of a timed test'
+    print('\n{s:s}{border:s}\n\n{n_s:s}: {n:,d}, {args_s:s}: {args:20s}{kwargs_s:s}: {kwargs:20s}\n'.format(**{
+        's':        s,
+        'border':   pp.ps(gen_border(), 'brightyellow'),
+        'n_s':      pp.ps('n', 'bold'),
+        'n':        test.n,
+        'args_s':   pp.ps('args', 'bold'),
+        'args':     _truncate(str(test.args)+', '),
+        'kwargs_s': pp.ps('kwargs', 'bold'),
+        'kwargs':   _truncate(str(test.kwargs)),
+    }))
+
+def _print_result_header(width: int=1) -> None:
+    msg = '{funcs:s}{status:<5s} {sep:s} {total:^10s} {sep:s} {median:^10s}'.format(**{
+        'funcs':  f'{"function":<{width}s}'.format('function'),
+        'status': 'status',
+        'total':  'Σ ',
+        'median': 'x̄',
+        'sep':     HEADER_SEP,
+    })
+    border = BORDER_SEP*len(msg)
+    print(msg, border, sep='\n')
+
+def _print_result(func: Callable, result: Any, correct: bool, times: Counter, width: int=1, colour: str='', extra: str='') -> None:
+    fail_sep, status_msg = '\n', ''
+    if not correct:
+        if os.get_terminal_size().columns >= 100:
+            fail_sep = ' '
+        result = _truncate(str(result))
+        status_msg = pp.ps(f'{fail_sep}>> {result=}', 'yellow')
+
+    msg = '{func_name:s}{status:<s}   {sep:s} {total:s} {sep:s} {median:s} {extra:s}{status_msg:s}'.format(**{
+        'func_name':  pp.ps(f'{func.__module__+"."+func.__name__+", ":<{width}s}', style=colour),
+        'total':      _format_time(_sum_times(times)),
+        'median':     _format_time(_median_times(times)),
+        'status':     TEST_STATUS[correct],
+        'extra':      extra,
+        'status_msg': status_msg,
+        'width':      width+2,
+        'sep':        RECORD_SEP,
+    })
+    print(msg)
+
+
+def timeit(n=10_000):
+    'Decorator to time a function'
+    def decorator_with_args(func):
+        @wraps(func)
+        def wrapper(*args, **kwargs):
+            result, correct, times = timeit_func(func, args, kwargs, NoExpectation, n)
+            _print_result(func, result, correct, times)
+        return wrapper
+    return decorator_with_args
+
+
+def bench(tests, func_groups, n: int=10_000, sort: bool=False):
+    'Run a series of timed tests on a list of functions'
+    s, group_colours = '', ['yellow', 'brightred', 'cyan', 'bold']
+
+    if os.environ.get('DEBUG'):
+        pp.ppd({'tests': tests, 'func_groups': func_groups, 'n': n, 'sort': sort}, indent=None)
+    for func_group in func_groups:
+        for func in func_group:
+            set_function_module(func)
+    width = max(len(func.__module__)+len(func.__name__)+3 for func in chain.from_iterable(func_groups))
+
+    if 'BENCH_SORT' in os.environ:
+        sort = True
+
+    for test in tests:
+        test, results = Test(*test, n=n), []
+        _print_header(s, test)
+        pp.pps('results:', 'bold')
+        _print_result_header(width)
+        for funcs, group_colour in zip(func_groups, group_colours):
+            for func in funcs:
+                result, correct, times = timeit_func(func, *test)
+                _print_result(func, result, correct, times, width, group_colour)
+                results.append((func, result, correct, times, width, group_colour))
+        if sort:
+            pp.pps('\nsorted by time:', 'bold')
+            _print_result_header(width)
+            base, extra = 0, ''
+
+            for _, results in enumerate(sorted(results, key=lambda r: _median_times(r[3]))):
+                if not results[2]:
+                    continue
+                if base == 0:
+                    base = _median_times(results[3])
+                else:
+                    x = _median_times(results[3]) / base
+                    extra = pp.ps(f' ↓ x{x:.2f}', 'bold')
+                _print_result(*results, extra=extra)
+        s = '\n'