occur cocur occur cocur ccour ccour ocucr coucr ouccr uoccr cuocr ucocr ocucr coucr ouccr uoccr cuocr ucocr ccuor ccuor cucor uccor cucor uccor occru cocru occru cocru ccoru ccoru ocrcu corcu orccu roccu crocu rcocu ocrcu corcu orccu roccu crocu rcocu ccrou ccrou crcou rccou crcou rccou ocurc courc oucrc uocrc cuorc ucorc ocruc coruc orcuc rocuc crouc rcouc ourcc uorcc orucc roucc urocc ruocc curoc ucroc cruoc rcuoc urcoc rucoc ocurc courc oucrc uocrc cuorc ucorc ocruc coruc orcuc rocuc crouc rcouc ourcc uorcc orucc roucc urocc ruocc curoc ucroc cruoc rcuoc urcoc rucoc ccuro ccuro cucro uccro cucro uccro ccruo ccruo crcuo rccuo crcuo rccuo curco ucrco cruco rcuco urcco rucco curco ucrco cruco rcuco urcco rucco
Note: these 'words' (valid or invalid) are all the permutations of the word occur. These words are obtained by scrambling the letters in occur.