I have a new skill to add to my CV: 'proficient with Gripples (all sizes)'. The Gripple (pictured below) is a pleasing little steel pebble with two thin hollow tubes running through it. It is engineered so that wire may pass nonchalantly through a tube in one direction but can not be pulled back out the same way. You can therefore attach two lengths of wire together. It is crucial, I understand, for the fencing industry. Crucial for vineyards too. This week I got to grips with the Gripple, as we installed a third horizontal wire on the trellising for some young vines. The plants are about 18 months old and...