This code is good for qbasic version 4.5 and others.
screen 13
FOR x = 0 TO 320 STEP 40
FOR time = 1 TO 100000
NEXT time
c = c + 1
LINE (x,0)-(x + 40,200), c, BF
NEXT x
CLS
t! = INT(TIMER)
DO
press$ = INKEY$
IF t! <> INT(TIMER) THEN
t! = INT(TIMER)
sec = sec + 1
IF sec > 59 THEN min = min + 1
IF sec > 59 THEN sec = 0
IF min > 59 THEN hr = hr + 1
IF min > 59 THEN min = 0
LOCATE 1, 1: PRINT USING "###"; hr; min; sec
LOCATE 1, 4: PRINT ":"
LOCATE 1, 7: PRINT ":"
END IF
LOOP UNTIL press$ = CHR$(27)
LINE (100, 0)-(200, 100), 4, BF 'create red box
a$ = INPUT$(1) 'wait for 1 key
FOR i = 42 TO 0 STEP -1
j = 42 - i
OUT &H3C8, 1 'access color 1(blue)
OUT &H3C9, j 'set red tone to j
OUT &H3C9, 0 'set green tone to 0
OUT &H3C9, i 'set blue tone to i
OUT &H3C8, 4 'access color 4(red)
OUT &H3C9, i 'set red tone to i
OUT &H3C9, 0 'set green tone to 0
OUT &H3C9, j 'set blue tone to j
FOR k = 1 TO 250000: NEXT k 'loop as a timer so you can see the transition
NEXT i
END