The animations are customizable. They can be added or deleted from the code. If you like an animation that was provided with the clock you can have a look at the code and copy it. Then you can change it as you like – new colors, a different speed, apply it to different digits… You can also pick different colors for each digit or all digits.
This way, the animation involving the way the clock jumps from 9 to 0 can be changed or turned off. The clock comes with several files that already include other “themes” without this particular animation.
Please read the section “Customizing the LED-Nixie Clock” to find out how exactly you can change the settings of the clock.