Ocado sell umbrella lolly moulds (£5 for a set of 6), that are perfect for the pen shape, but any thin ice-lolly set will work.
Pour each cordial into a separate jug,
and add the corresponding food
colouring. Stir in 100ml water. Put the
blueberries, strawberries and grapes
into the ice-lolly moulds and pour the
blackcurrant mixture up to the brim of
3 moulds. Pour the orange cordial into
the remaining 3 moulds. Freeze for 4 hrs.
Remove the lollies from the moulds and
dot extra food colouring onto a dish. Dip
the lollies into the colouring and use to
draw on clean paper – while enjoying
the lolly at the same time.