In tax evasion cases, affirmative willful attempt to evade payment of taxes may be inferred from conduct such as keeping a double set of books, making false entries of alterations, or false invoices or documents, destruction of books or records, concealment of assets or covering up sources of income, handling of one's affairs to avoid making the records usual in transactions of the kind, and any conduct, the likely effect of which would be to mislead or to conceal.