In 1750 Alexander, 10th Earl of Eglinton, repaired the castle, converting it into a folly. The four open and four closed pointed windows were constructed for appearance only at this time and on the west side an armorial panel stone with the Earl of Eglinton's arms was put in place. Through some mistake this panel was said to have been placed upside down; however, the shield is actually the right way up. The apparent fault is that the signet rings and fleur de lis inside are upside down. Another error occurs on a similar-sized armorial panel now preserved in the quadrangle of Eglinton Country Park in which the symbols are in the wrong quarters. An original feature is a spiral stair in the north-east corner.