Next job, remove the tape sealing the box at the bottom end so you can open it up fully, most important for this alteration project...........(all the time I am being closely watched remember.....)
A black sharpie is perfect for the next step but make sure your customer does not get hold of it in an effort to assist you as you appear to be dawdling!! Draw some random lines through the base of the box from one side to the other then make short sharp lines joining the longer lines together.
You will now need a second, smaller box, size won't really matter as long as it will fit through the larger box. Tuck the flaps of the box inside to create a flat base once you invert the box.
Rescuing the black sharpie from your customer who stole it while you were folding in the flaps of the box, now make some random marks on the outside of the smaller box.Once your customer has given the smaller box his seal of approval and in honour of your efforts named it 'Thomas'
You can leave him to play with his new train and tunnel!!
My customer? Sam, my two year old grandson who appeared unexpectedly today at the shop and we needed something to amuse and fast.................his current fixation is Thomas and tunnels. Please feel free to use this design :))