diff --git a/lang/funcs/core/fmt/printf_func.go b/lang/funcs/core/fmt/printf_func.go
index 34326212..4057cc83 100644
--- a/lang/funcs/core/fmt/printf_func.go
+++ b/lang/funcs/core/fmt/printf_func.go
@@ -379,6 +379,14 @@ func (obj *PrintfFunc) Close() error {
 // valueToString prints our values how we expect for printf.
 // FIXME: if this turns out to be useful, add it to the types package.
 func valueToString(value types.Value) string {
+	switch x := value.Type().Kind; x {
+	// FIXME: floats don't print nicely: https://github.com/golang/go/issues/46118
+	case types.KindFloat:
+		// TODO: use formatting flags ?
+		// FIXME: Our String() method in FloatValue doesn't print nicely
+		return value.String()
+	}
+
 	// FIXME: this is just an "easy-out" implementation for now...
 	return fmt.Sprintf("%v", value.Value())
 
diff --git a/lang/funcs/core/math/fortytwo_func.go b/lang/funcs/core/math/fortytwo_func.go
new file mode 100644
index 00000000..02bd268e
--- /dev/null
+++ b/lang/funcs/core/math/fortytwo_func.go
@@ -0,0 +1,69 @@
+// Mgmt
+// Copyright (C) 2013-2021+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package coremath
+
+import (
+	"fmt"
+
+	"github.com/purpleidea/mgmt/lang/funcs/simplepoly"
+	"github.com/purpleidea/mgmt/lang/types"
+)
+
+func init() {
+	typInt := types.NewType("func() int")
+	typFloat := types.NewType("func() float")
+	simplepoly.ModuleRegister(ModuleName, "fortytwo", []*types.FuncValue{
+		{
+			T: typInt,
+			V: fortyTwo(typInt), // generate the correct function here
+		},
+		{
+			T: typFloat,
+			V: fortyTwo(typFloat),
+		},
+	})
+}
+
+// fortyTwo is a helper function to build the correct function for the desired
+// signature, because the simplepoly API doesn't tell the implementing function
+// what its signature should be! In the next version of this API, we could pass
+// in a sig field, like how we demonstrate in the implementation of FortyTwo. If
+// the API doesn't change, then this is an example of how to build this as a
+// wrapper.
+func fortyTwo(sig *types.Type) func([]types.Value) (types.Value, error) {
+	return func(input []types.Value) (types.Value, error) {
+		return FortyTwo(sig, input)
+	}
+}
+
+// FortyTwo returns 42 as either an int or a float. This is not especially
+// useful, but was built for a fun test case of a simple poly function with two
+// different return types, but no input args.
+func FortyTwo(sig *types.Type, input []types.Value) (types.Value, error) {
+	if sig.Out.Kind == types.KindInt {
+		return &types.IntValue{
+			V: 42,
+		}, nil
+	}
+	if sig.Out.Kind == types.KindFloat {
+		return &types.FloatValue{
+			V: 42.0,
+		}, nil
+	}
+	return nil, fmt.Errorf("unknown output type: %+v", sig.Out)
+}
diff --git a/lang/interpret_test/TestAstFunc2/fortytwo.output b/lang/interpret_test/TestAstFunc2/fortytwo.output
new file mode 100644
index 00000000..a8afdb37
--- /dev/null
+++ b/lang/interpret_test/TestAstFunc2/fortytwo.output
@@ -0,0 +1,2 @@
+Vertex: test[float: 42]
+Vertex: test[int: 42]
diff --git a/lang/interpret_test/TestAstFunc2/fortytwo/main.mcl b/lang/interpret_test/TestAstFunc2/fortytwo/main.mcl
new file mode 100644
index 00000000..3e888213
--- /dev/null
+++ b/lang/interpret_test/TestAstFunc2/fortytwo/main.mcl
@@ -0,0 +1,6 @@
+import "fmt"
+import "math"
+# FIXME: floats don't print nicely: https://github.com/golang/go/issues/46118
+# FIXME: This means that we see "42" for both, instead of 42.0 ...
+test fmt.printf("int: %d", math.fortytwo()) {}
+test fmt.printf("float: %f", math.fortytwo()) {}
diff --git a/lang/types/value.go b/lang/types/value.go
index f428d164..7022c0d5 100644
--- a/lang/types/value.go
+++ b/lang/types/value.go
@@ -708,6 +708,7 @@ func NewFloat() *FloatValue { return &FloatValue{} }
 // String returns a visual representation of this value.
 func (obj *FloatValue) String() string {
 	// TODO: is this the right display mode?
+	// FIXME: floats don't print nicely: https://github.com/golang/go/issues/46118
 	return strconv.FormatFloat(obj.V, 'f', -1, 64) // -1 for exact precision
 }