Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	May 31, 2023	May 31, 2022
Operating activities
Net income	$ 6,287,358	$ 2,239,423
Adjustments to reconcile net income to net cash flows from operating activities
Depreciation	1,472,455	1,347,442
Stock options issued for services	417,253	201,278
Bad debt expense	23,360	0
(Gain) loss on disposal of property and equipment	20,015	(1,530)
Provision for inventory obsolescence	295,014	0
Deferred income taxes	(494,000)	115,500
Changes in other current assets and liabilities
Accounts and other receivables	(1,110,178)	(346,122)
Inventory	(277,214)	486,191
Prepaid expenses	28,882	54,258
Prepaid income taxes	7,000	218,831
Costs and estimated earnings in excess of billings	(787,708)	(1,836,870)
Accounts payable	290,827	(360,495)
Accrued expenses	664,008	1,429,841
Billings in excess of costs and estimated earnings	869,707	(239,222)
Net operating activities	7,706,779	3,308,525
Investing activities
Acquisition of property and equipment	(3,359,495)	(1,391,577)
Proceeds from disposal of property and equipment	0	7,500
Increase in short-term investments	(23,417,307)	(438)
Increase in cash value of life insurance	(4,761)	(4,821)
Net investing activities	(26,781,563)	(1,389,336)
Financing activities
Proceeds from issuance of common stock	302,705	16,245
Acquisition of treasury stock	(169,740)	0
Net financing activities	132,965	16,245
Net change in cash and cash equivalents	(18,941,819)	1,935,434
Cash and cash equivalents - beginning	22,517,038	20,581,604
Cash and cash equivalents - ending	$ 3,575,219	$ 22,517,038