create a 3d rendering of a concrete storage clamp containing whole crop maize for an anaerobic digestion plant, on a flat white background. The clamp should be rectangular and its length should be twice its wide. It should have an open entrance on one of the short sides that will allow a tractor to drive directly into it, the entrance ot the clamp should be at ground level and pointing in a south-east direction. Viewed from an elevated position at a 60 degree angle