Like any new process, it takes some practice to extract, understand and convert the information presented from a set of experimental NMR datasets into a fragment.
The only fragment that can accommodate the set of restrictions from a 1H-13C HSQC and HMBC is 2,3-dimethylbutane-1,1-diyl. The green arrows illustrate the 2-3JCH coupling responses extracted from an HMBC experiment.