scoreboard players add @s KyuDummy 0


execute at @s run execute store result score @s KyuDummy run fill ~-17 64 ~-17 ~17 64 ~17 bedrock replace blue_terracotta
execute at @s[type=!player,scores={KyuDummy=1..}] run fill ~-17 64 ~-17 ~17 64 ~17 blue_terracotta replace bedrock
execute at @s[type=!player,scores={KyuDummy=1..}] run scoreboard players add @s KyuDummy 1

#if any one block check fails, kill the marker
kill @s[type=!player,scores={KyuDummy=..1}]